In a period of galactic civil war, Rebel Alliance spies have stolen blueprints to the Death Star, a colossal space station built by the Galactic Empire that is capable of destroying entire planets. Princess Leia Organa of Alderaan, secretly a rebel leader, has obtained the schematics, but her ship is intercepted and boarded by Imperial forces under the command of Darth Vader. Leia is taken prisoner, but the droids R2-D2 and C-3PO escape with the plans, crash-landing on the nearby desert planet of Tatooine. Darth Vader orders his troops to pursue the droids. The droids are captured by Jawa traders, who sell them to the moisture farmers Owen and Beru Lars and their nephew, Luke Skywalker. While Luke is cleaning R2-D2, he discovers a recording of Leia requesting help from a former ally named Obi-Wan Kenobi. R2-D2 goes missing, and while searching for him, Luke is attacked by Sand People. He is rescued by the elderly hermit Ben Kenobi, who soon reveals himself as Obi-Wan. He tells Luke about his past as one of the Jedi Knights, peacekeepers of the former Galactic Republic, who drew mystical abilities from the Force and were all but exterminated by the Empire. Luke learns that his father, also a Jedi, fought alongside Obi-Wan during the Clone Wars until Vader, Obi-Wan's former pupil, turned to the dark side of the Force and murdered him. Obi-Wan gives Luke his father's lightsaber, the signature weapon of the Jedi. R2-D2 plays Leia's full message, in which she begs Obi-Wan to take the Death Star plans to Alderaan and give them to her father, a fellow veteran, for analysis. Luke initially declines Obi-Wan's offer to accompany him to Alderaan and learn the ways of the Force. However, he quickly changes his mind after Imperial stormtroopers murder his family and destroy his home while searching for the droids. Seeking a way off the planet, Luke and Obi-Wan travel with the droids to the city of Mos Eisley and hire the smuggler Han Solo and his Wookiee partner Chewbacca, pilots of the starship Millennium Falcon. On the way to Alderaan, Obi-Wan begins Luke's training in the use of the Force. Meanwhile, the Death Star commander Grand Moff Tarkin has Alderaan obliterated by the station's superlaser. The Death Star's tractor beam captures the Falcon, but Luke and his companions manage to avoid detection and infiltrate the station. Vader, however, senses Obi-Wan's presence, and begins searching for him. As Obi-Wan deactivates the tractor beam, Luke persuades Han and Chewbacca to help him rescue Leia, who is scheduled for execution after refusing to reveal the location of the rebel base. After disabling the tractor beam, Obi-Wan sacrifices himself in a lightsaber duel against Vader, which allows the rest of the group to escape. Using a tracking device placed on the Falcon, the Empire locates the rebel base on the moon Yavin 4. Analysis of the Death Star schematics reveals a weakness in a small exhaust port leading directly to the station's reactor. Luke joins the Rebellion's X-wing squadron in a desperate attack against the Death Star, while Han and Chewbacca leave to pay off a debt to the crime lord Jabba the Hutt. In the ensuing battle, Vader leads a squadron of TIE fighters and destroys several rebel ships, while Tarkin prepares to destroy Yavin 4 with the Death Star. Han and Chewbacca unexpectedly return in the Falcon, knocking Vader's ship off course before he can shoot Luke down. Guided by the voice of Obi-Wan's spirit, Luke uses the Force to aim his torpedoes into the exhaust port, causing the Death Star to explode moments before it can fire on the rebel base. In a triumphant ceremony, Leia awards Luke and Han medals for their heroism.

In a distant galaxy, a starship searches for the evil Count Zarth Arn. Closing in on a planet, the ship is attacked by a mysterious weapon which drives the crew insane. Three escape pods launch, but the ship crashes into the atmosphere of the planet and is destroyed. Meanwhile, smugglers Stella Star and Akton run into the Imperial Space Police, led by robot sheriff Elle and Police Chief Thor. Akton and Stella escape by jumping into hyperspace. When they emerge, they discover an escape pod from the attacked starship, and in it, a disoriented survivor. The police track their hyperspace trail and apprehend them. Tried and convicted of piracy, they are sentenced to life in prison on separate planets. Stella escapes from her prison, but Elle and Thor recapture her, only to inform her the authorities have canceled her sentence; she is taken to an orbiting ship, where she is reunited with Akton. They are contacted by the Emperor of the Galaxy, who thanks them for recovering the starship survivor. The Emperor orders Stella and Akton to find a secret weapon of immense power which Count Zarth Arn has hidden away. They are offered clemency if they help find two more missing escape pods as well as the mothership, one of which may contain the Emperor's only son. Accompanied by Thor and Elle, Stella and Akton arrive at the location Akton computes for the first escape pod. Stella and Elle take a shuttle and land near the pod on a beach. There are no survivors. Stella meets an Amazonian warrior tribe and is escorted to their underground fortress. On arrival, Elle is ambushed, shot and left for dead, and Stella is taken before Amazon Queen Corelia, who is in league with Zarth Arn. Elle, revealed not to have died, makes his way to the throne room, taking Corelia hostage to secure Stella's release. They escape, but the queen activates a giant robot which chases them until they are rescued by Akton and Thor. On an uninhabited, frozen planet, Stella and Elle investigate the mothership crash site. They find no survivors. Upon their return to the ship, Thor, who has ambushed and apparently knocked out Akton, reveals that he is an agent of Zarth Arn. Thor locks Stella and Elle outside on the planet's surface, where the temperature drops thousands of degrees at night. Elle preserves Stella's life by using his energy to keep her heart going while they freeze over in the snow. Akton revives and battles Thor, killing him and subsequently rescuing Elle and Stella. Approaching the planet of the third escape pod, their ship comes under attack from the weapon which downed the starship. Akton steers the ship through it, saving them. Stella and Elle, inspecting the pod wreckage, are attacked by cavemen who smash Elle to pieces and abduct Stella. The Emperor's son, Prince Simon, arrives and rescues her by firing lasers through his eyes. They are again attacked and overpowered by the cavemen, but Akton appears and fights them off with his laser sword; he then reveals that they are standing on the Count's weaponized planet. Arriving at an underground laboratory, the three are captured by guards. The Count appears and reveals his plan to use them as bait to bring the Emperor to the planet and then have his weapon self-destruct, destroying the planet, the Emperor and all three of them. He leaves, ordering his two robot golems to keep the group there. Akton engages them in a laser sword duel and defeats the robots, but is mortally wounded by one of them and fades away, thanks to Simon's assistance, which helps to continue the duel with one of them. The Emperor arrives and fires a green ray from his flagship to "stop time" for three minutes, allowing them all to escape as the planet explodes. A battle commences between the Emperor's armada and the Count's, with the Emperor's soldiers storming the Count's space station. The attack fails and the victorious Count gets ready to destroy the Emperor's home planet. The Emperor decides to ram the Count's space station with a massive space station, the Floating City, in a 4th dimensional attack, “Starcrash”. Elle has been rebuilt by the Emperor's men. Stella and Elle fly the City towards the space station and escape together just as their station crashes into the Count's, winning the war. Stella and Elle are picked up by Simon and the two humans embrace. The Emperor delivers a victory speech.

In 1964, eight-year-old Allen Bauer and his family are taking a boat tour at Cape Cod, Massachusetts. Allen is fascinated by something below the surface and jumps overboard, even though he cannot swim. In the ocean, he encounters a young girl, and when they hold hands, he inexplicably finds himself able to breathe underwater. However, Allen is rescued and pulled back to the surface, and the two are separated. Since no one else saw the girl, Allen comes to believe the encounter was a near-death hallucination. After the boat pulls away, the young girl is revealed to be a mermaid. Twenty years later, Allen is now co-owner of a wholesale fruit and vegetable business in New York City with his womanizing older brother, Freddie. Throughout the years, Allen's relationships have failed as he subconsciously seeks the connection he shared with the mermaid. Depressed after his latest breakup, Allen returns to Cape Cod, where he encounters eccentric scientist Walter Kornbluth on a diving expedition. When his motorboat restarts, Allen falls into the sea and is knocked unconscious; his wallet drops onto the coral below. He later wakes up on a beach, with a headache from the accident, in the presence of a beautiful, naked young woman who is unable to talk. After kissing Allen, the woman dives into the sea, where she transforms into a mermaid. While swimming underwater, she is sighted by Kornbluth. The mermaid finds Allen's wallet and uses a sunken ship's charts to locate New York. She comes ashore naked at the Statue of Liberty and is arrested for indecent exposure. Using information from the wallet, the police contact Allen, and she is released into his care. The mermaid learns how to speak English from watching television and is eager to explore the city. Unable to say her real name in human language, she selects "Madison" from a Madison Avenue sign. She tells Allen that she will be in New York for "six fun-filled days, and the moon is full", unable to return home if she stays any longer. Despite Madison's occasionally outlandish behavior, she and Allen fall in love. He proposes to her, but she declines and runs away. After some contemplation, Madison returns to Allen and agrees to marry him, with the added promise of telling him the truth about herself after an upcoming dignitary dinner to welcome the President. Meanwhile, Kornbluth, realizing that Madison is the mermaid he encountered, pursues the couple, trying to expose her by splashing her with water. After his first attempts are unsuccessful, Kornbluth ultimately infiltrates the dignitary dinner, soaking Madison with a hose and unmasking her identity. Madison is seized by government agents and taken to a secret lab, headed by Kornbluth's cold-hearted rival, Dr. Ross, for examination. As she withers away in captivity, Kornbluth learns that the scientists are planning to dissect her, causing him to regret his actions. Allen is shocked by Madison's secret and rejects her, but when he voices his disillusionment to his brother, Freddie berates him, reminding him how happy he was with her. Realizing that he still loves Madison, Allen confronts the guilt-ridden Kornbluth, who, having been rejected by his colleagues despite proving the existence of mermaids, agrees to help rescue her. Kornbluth, accompanied by Allen and Freddie impersonating Swedish scientists, enters the lab and smuggles Madison outside. Freddie stays behind to be arrested in Allen's place, while Kornbluth unsuccessfully tries to stop military troops from catching the couple. As they make it to New York Harbor, Madison tells Allen that he can survive underwater as long as he is with her, prompting Allen to realize that she was the girl he had met underwater as a child. She warns him that if he comes to live in the sea, he will never be able to return to land. Madison dives into the water as the troops close in on them. When they attempt to arrest Allen, he jumps in after her but starts to drown. She kisses him, gifting him the ability to swim and breathe underwater. Frogmen try to recapture them, but the couple fight them off and escape. Allen discards his jacket as the couple happily swims toward what appears to be an underwater kingdom.

Starman is a love story. It's It Happened One Night — John Carpenter The Voyager 2 space probe, launched in 1977, carries a phonographic disc with a message of peace, inviting alien civilizations to visit Earth. The probe is intercepted by an alien ship traveling through space which then sends a scout vessel to establish first contact with Earth. Instead of greeting the vessel, the U.S. government shoots it down. Crashing in Chequamegon Bay, Wisconsin, the lone alien occupant, looking like a floating ball of energy, finds the home of recently widowed Jenny Hayden. He uses a lock of hair from her deceased husband Scott, to clone a body for himself. The alien "Starman" has seven spheres with him which provide energy to perform miraculous feats. The alien uses the first sphere to send a message to his people stating that Earth is hostile and his spacecraft was destroyed. He arranges to rendezvous with them in three days' time. He then uses the second sphere in self-defense and the third to create a holographic map of the United States, coercing Jenny into taking him to the rendezvous in Arizona. Jenny, however, attempts to escape. Having a very basic understanding of the English language from the phonographic disk, the Starman learns to communicate with Jenny and assures her that he means no harm. He explains that if he does not reach the rendezvous point, Arizona's Barringer Crater, in three days, he will die. Jenny teaches the Starman how to drive a car and use credit cards, so he can continue the journey alone. When he resurrects a dead deer, she is moved and decides to stay with him. The authorities pursue the pair across the country. A police officer shoots and critically wounds Jenny. To escape, the Starman crashes their car into a gas tanker and uses another sphere to protect them from the explosion. They take refuge in a mobile home that is being towed. He uses another sphere to heal Jenny. After being assured that she will recover, he proceeds to hitchhike toward Arizona without her, but Jenny reaches him while he and his driver are stopped at a roadblock. Reunited, they hitchhike together, resuming their journey towards the crater. Later, while stowing away on a railroad boxcar, the two have sex. The Starman tells Jenny, "I gave you a baby tonight." She reveals that she is infertile, but he assures her that she is pregnant. He explains that Scott is the posthumous father, as Starman used Scott's DNA to clone himself. As a child also of Starman, their son will possess all the Starman's knowledge and will grow up to be a teacher. Starman offers to stop the pregnancy if she wishes, but Jenny embraces him, accepting the gift. They accidentally travel too far on the train and arrive in Las Vegas. Jenny loses her wallet. The Starman uses one of their last quarters in a slot machine, which he manipulates to win the $500,000 jackpot. They buy a Cadillac to complete their journey to Arizona. National Security Agency director George Fox learns that the Starman's flight trajectory, prior to being shot down, was to the Barringer Crater. So, he arranges to have the Army capture the Starman, dead or alive. SETI scientist Mark Shermin, another government official involved in the case, criticizes Fox's heavy-handed approach and reminds him that the Starman was invited to Earth. Appalled to learn that Fox is planning to vivisect the alien, Shermin then resolves to help the Starman escape rather than let Fox capture him. Jenny and the dying Starman reach the crater as Army helicopters pursue them. Just as they are surrounded, a large spaceship appears and descends into the crater. Light surrounds the couple and the Starman is fully healed. While preparing to leave, he tells Jenny he will never see her again. Jenny asks him to take her with him, but he says she would die on his world. He then gives her his last sphere, saying that their son will know what to do with it. Jenny watches as the ship departs.

Recent Georgetown University graduates Alec Newberry, Leslie Hunter, Kevin Dolenz, Jules Van Patten, and Kirby Keager wait to hear about the conditions of their friends: Wendy Beamish, a sweet-natured young woman devoted to helping others, and Billy Hicks, a former fraternity boy and now reluctant husband and father, after a minor car accident caused by Billy's drinking. At the hospital, Kirby spots an intern named Dale Biberman, with whom he has been infatuated since college. The group gathers at their favorite college hangout, St. Elmo's Bar. Billy has been fired from the job that Alec helped him secure. At their apartment, Alec pressures Leslie to marry him, but she thinks they are unprepared. Kirby is telling Kevin of his love for Dale when Billy shows up, asking to spend the night as he cannot cope with his wife Felicia. Jules accuses Kevin of being gay and loving Alec. When Kevin visits Alec and Leslie for dinner, Alec confesses to Kevin that he recently had sex with a lingerie saleswoman. Billy and Wendy get drunk together, and Wendy reveals that she is a virgin. They kiss, and Billy, tugging at her clothing, makes fun of her girdle. Wendy insists they remain platonic friends. At St. Elmo's during a Halloween party, Jules reveals to Leslie that she is having an affair with her married boss Forrester Davidson. Billy sees Felicia with another man in the crowd and attacks him. Billy is thrown out of the bar but reconciles with Felicia. The women confront Jules about her affair and reckless spending, but she insists that everything is under control. Kirby takes a job working for Kim Sung Ho, a wealthy Korean businessman, and invites Dale to a party at Mr. Kim's house, which he is using without Mr. Kim's permission. Wendy arrives with Howie Krantz, an ungainly Jewish boy whom her parents want her to marry. Alec announces that he and Leslie are engaged, upsetting her. She confronts him about her suspicions of his infidelity, and the two break up. Alec accuses Kevin of telling Leslie about the tryst with the lingerie woman. Jules gives Billy a ride home, and Billy makes a pass at her. Furious, Jules orders him out of her car; Felicia witnesses the confrontation. When Dale skips the party, Kirby drives to the ski lodge where she is staying and meets her boyfriend Guy. Kirby's borrowed car gets stuck, and Dale and Guy invite him in. The next morning, as Kirby prepares to leave the lodge, Dale tells him that she is flattered by his interest in her. He kisses her, and then Guy takes a photo of them before he leaves. Leslie goes to Kevin's apartment to spend the night after the breakup and discovers photographs of her. Kevin confesses his love for her, and the two have sex. Alec goes to the apartment to apologize to Kevin and finds Leslie there. Wendy tells her father that she wants to be independent and move into her own place. Jules has been fired from her job, fallen behind on her credit card payments, and her possessions have been seized. She locks herself in her apartment and opens the windows, intending to freeze to death. Her friends attempt to coax her out, but she is unresponsive. Kirby fetches Billy, who landed a job at a gas station courtesy of Kevin, to calm Jules down. Billy convinces Jules to let him in, and they talk about the challenges of life, overheard by the rest of the gang. Wendy moves into her own place; Billy visits and informs her that he is getting a divorce and moving to New York City to try making it as a musician, and the two have sex. At the bus station, the group gathers once more to say goodbye to Billy. Billy urges Alec to make up with Leslie, but she declares that she does not want to date anyone for a while. Alec and Kevin make up, and the group makes plans to meet for brunch. However, they decide not to go to St. Elmo's and instead choose Houlihan's because there are "not so many kids" there.

The crew of the newly commissioned USS Enterprise (NCC-1701-A) are enjoying shore leave after the starship's shakedown cruise, with Kirk, Spock, and McCoy camping at Yosemite National Park. Their leave is interrupted when the Enterprise is ordered by Starfleet Command to rescue a human, a Klingon, and a Romulan, all diplomats who have been taken hostage on Nimbus III, a planet set aside as a neutral location to advance dialogue among the Federation, Klingon Empire, and Romulan Star Empire. Learning of the Enterprise ' s mission, the ambitious Klingon Captain Klaa decides to pursue Kirk for personal glory. On Nimbus III, the Enterprise crew discovers that Sybok, a renegade Vulcan, is behind the hostage crisis, prompting Spock to admit that Sybok is his half-brother. After the Enterprise crew saves the hostages, Sybok reveals that the hostage-taking was a ruse to lure a starship, which he plans to use to travel to the mythical planet Sha Ka Ree. Sybok believes it lies behind the Great Barrier, a powerful energy field at the galaxy's center, and that God is located there. To take control of the ship, Sybok uses his ability to reveal and heal the innermost pain of a person through the Vulcan mind meld, thus gaining the loyalty of most of the crew. McCoy's pain is that he had helped fulfill his terminally ill father's request to die, only to find later that a cure could have saved his father's life, which has caused him years of guilt. Spock's pain is the knowledge that his father rejected him at birth for being "too human". Kirk refuses to let Sybok remove his pain, claiming that it is necessary to make him human. The Enterprise successfully breaches the Great Barrier, unaware they are being followed by Captain Klaa's warship, a Klingon bird-of-prey. They discover a lone barren planet, and Sybok, Kirk, Spock, and McCoy take a shuttlecraft down to the surface. It appears uninhabited, but after Sybok calls out, a glowing field appears which quickly morphs through many forms representing various religions before settling into the image of a bearded human face, to which Sybok explains that they have come for "your wisdom". The entity asks how they breached the barrier, and upon being told about the Enterprise, it declares that it will use the ship to carry its wisdom to every corner of the universe. A skeptical Kirk asks "What does God need with a starship?", and when the entity asks who he is, Kirk expresses doubt that the actual supreme being would not already know. Irritated, the entity attacks him and Spock, after which they discover it is a powerful and malicious being, imprisoned on Sha Ka Ree in the distant past, with the Great Barrier put in place to keep it from escaping. Realizing his earlier naiveté, Sybok apologizes and attempts to distract the entity by physically attacking it, allowing the others the opportunity to escape. Kirk orders the Enterprise to fire a photon torpedo at the entity, but only Sybok is killed by the strike. Spock and McCoy beam back to the ship moments before the Klingon ship unexpectedly attacks and damages the Enterprise, stranding Kirk on the planet with the weakened and enraged entity. As Kirk attempts to escape from the entity, the Klingon Bird of Prey arrives and destroys the entity with a volley of disruptor fire. Kirk is beamed aboard the Klingon ship, where Spock is unexpectedly waiting. As Spock explains, he convinced the Klingon General Korrd (one of Sybok's hostages who had become a loyal follower) to order Captain Klaa to stand down and apologize for his actions, which Klaa grudgingly does. After returning to Earth, Kirk, Spock, and McCoy resume their camping trip at Yosemite.

In 2293, the Federation starship Excelsior, commanded by Captain Hikaru Sulu, discovers that the Klingon moon of Praxis has been destroyed in a mining accident. The loss of Praxis and the ecological devastation of the Klingon homeworld throws the Klingon Empire into turmoil. No longer able to afford war with the Federation, the Klingons pursue peace. Starfleet sends the Federation starship Enterprise to meet with the Klingon Chancellor Gorkon and escort him to negotiations on Earth. Enterprise Captain James T. Kirk, whose son David was murdered by Klingons, opposes peace and resents the assignment. Enterprise and Gorkon's battlecruiser rendezvous and continue towards Earth, with the two command crews sharing a tense meal. Later that night, Enterprise appears to fire torpedoes at the Klingon ship, disabling its artificial gravity. During the confusion, two men wearing Starfleet spacesuits and magnetic boots beam aboard the Klingon vessel, kill two crew members, and mortally wound Gorkon before escaping. Kirk surrenders to avoid armed conflict and beams aboard with Doctor Leonard McCoy to try and save Gorkon's life. The chancellor dies, and Gorkon's chief of staff, General Chang, arrests Kirk and McCoy for his assassination. A Klingon court finds the pair guilty and sentences them to life imprisonment on the frozen planetoid Rura Penthe. Gorkon's daughter Azetbur becomes the new chancellor and continues diplomatic negotiations; the conference is relocated for security, and the new location is kept secret. While several senior Starfleet officers want to rescue Kirk and McCoy, the Federation president refuses to risk full-scale war; Azetbur likewise refuses to invade Federation space. Kirk and McCoy arrive at the Rura Penthe mines and are befriended by Martia, a shapeshifter, who offers them an escape route; in reality, it is a ruse to make their arranged deaths appear accidental. Once her betrayal is revealed, Martia transforms into Kirk's double and fights him, but is killed by the prison governor to silence any witnesses. Kirk and McCoy are beamed aboard Enterprise by Spock, who has assumed command and launched an investigation in Kirk's absence. Determining that Enterprise did not fire the torpedoes, the crew searches for the assassins. Kirk and Spock set a trap to draw out the accomplice in sick bay and discover that the killer is Spock's protégé, Valeris. To find the identity of the other conspirators, Spock initiates a forced mind-meld and learns that Federation, Klingon, and Romulan officials conspired to sabotage the peace talks. The torpedoes that struck Gorkon's cruiser came from Chang's ship, which has the unique ability to fire its weapons while cloaked. Enterprise and Excelsior race to Khitomer, the location of the peace talks. Chang's cloaked ship attacks and inflicts heavy damage on Enterprise. At the suggestion of Spock and Uhura, Spock and McCoy modify a torpedo to home in on the exhaust emissions of Chang's ship. The torpedo impact reveals Chang's location, and Enterprise and Excelsior destroy his ship with a volley of torpedoes. The crews from both ships beam to the conference and thwart the assassination attempt on the Federation president's life. Starfleet Command orders Enterprise to return to Earth to be decommissioned. Kirk decides to take his ship on one last cruise instead, and notes in his log a new generation of explorers will continue their legacy.

Architect Sam Baldwin moves from Chicago to Seattle with his eight-year-old son, Jonah, to start a new life following the death of his beloved wife, Maggie. Over a year later, on Christmas Eve, Jonah calls a nationally syndicated radio talk show seeking advice on how to help his father find happiness again. He persuades a reluctant Sam to go on the air and talk about how much he misses Maggie. Sam describes her as his soulmate, explaining that he knew she was the one when he first took her hand and believes he could never find true love twice. Touched by his story, thousands of women across the country write to him. One listener is Annie Reed, a Baltimore Sun reporter. She is engaged to the sensible and supportive Walter, but feels something is missing from their relationship. Her friend and editor, Becky, suggests Annie longs for the kind of destined romance found "in a movie", although Annie dismisses the idea of magical love or fate. Inspired by the romance film An Affair to Remember, Annie writes Sam a letter proposing they meet atop the Empire State Building in New York City on Valentine's Day. She decides against sending it, but Becky secretly mails it. Encouraged by the response to his radio appearance and by his friends, Sam begins dating a co-worker, Victoria, whom Jonah vehemently dislikes. When Jonah reads Annie's letter, he instinctively believes she could be the one for his father, but Sam dismisses the idea because of the distance between Seattle and Baltimore. Jonah's friend Jessica urges him to reply on Sam's behalf, agreeing to the meeting. After Jonah calls the radio show again and reveals that Sam is dating, Annie travels to Seattle on a work assignment arranged by Becky as a pretext to learn more about him. While dropping Victoria off at the airport, Sam notices Annie leaving her flight and is immediately captivated by her, unaware of who she is. Later, Annie secretly watches Sam and Jonah playing together on the beach. The following day, she visits Sam's houseboat but mistakes his sister, Suzy, for Victoria. A passing vehicle nearly strikes Annie and sounds its horn, alerting Sam to her presence. They briefly stare at one another before Annie, embarrassed, leaves. Back in Baltimore, Annie reads Jonah's immature reply and concludes she has made a mistake pursuing Sam. She decides to commit to Walter and travel to New York to meet him on Valentine's Day. Meanwhile, Jessica uses her travel agent mother's computer to book Jonah a flight to New York to find Annie. When Sam learns where Jonah has gone, he flies after him, and they reunite on the Empire State Building's observation deck. During dinner with Walter, Annie confesses her doubts about their relationship, everything that has happened since hearing Sam's radio broadcast, and they amicably end their engagement. Seeing the Empire State Building illuminated in the shape of a heart, Annie takes it as a sign. She rushes there, arriving on the observation deck moments after Sam and Jonah have left in the elevator. When Sam and Jonah return to retrieve Jonah's misplaced backpack, Sam and Annie recognize each other. After introducing themselves, Annie takes Sam's hand, and the three leave together.

Charlie MacKenzie is a popular local beat poet living in San Francisco who makes his frequent break-ups the subject of his poems. His best friend Tony, a recently promoted police detective, believes that Charlie is afraid of commitment and will identify (or invent) any reason to break up with someone. While purchasing Haggis for his Scottish-born parents, Stuart and May, he encounters a butcher named Harriet, and is attracted to her. During his visit with his family, Charlie and May discuss his most recent break-up, and May brings up a tabloid article about a bride known as "Mrs. X", who kills her husbands on their honeymoons using an axe. Charlie goes back to the butcher shop and offers to help Harriet. The two find common bonds and start to date. After staying at her place one night, Charlie meets Harriet's eccentric sister, Rose, who warns Charlie to be careful. He learns Harriet used to live in Atlantic City, was involved with a trainer in Russian martial arts, and screams for someone named Ralph in her sleep. Charlie arranges a dinner with her to meet his parents, who say she is their favourite of all his partners. Charlie reads the article about Mrs. X, which identifies two of her victims as a martial arts expert and a man named Ralph. Charlie becomes fearful and asks Tony to investigate Harriet and the Mrs. X story. Tony reveals that the husbands of Mrs. X were all reported missing alongside their wives, assuring that Harriet is unlikely to be Mrs. X. Charlie remains on edge, and after a few more troubled dates, breaks up with her. Tony reports that a killer in the Mrs. X story has confessed. Relieved, Charlie apologizes to Harriet by reciting one of his beat poems to her from her rooftop. They make up, and Harriet explains away some of her history, such as Ralph being the name of a woman she knows. At his parents' wedding anniversary Charlie proposes to Harriet. She accepts after some hesitation. Following the wedding ceremony, they embark on a honeymoon to a secluded mountain hotel. After they depart, Tony learns that the confessed killer is actually a compulsive liar. He sends a photo of Harriet to the known associates of the missing husbands, and all identify her as their friends' wife. With phone lines to the hotel down due to a storm, Tony charters a plane. Once he lands, he calls Charlie locally and warns him that Harriet really is Mrs. X, but the hotel phone line is knocked out and power is lost. Charlie panics and tries to stay away from Harriet without letting her know what he knows, but the hotel staff force him into the honeymoon suite for their first night together. After locking Harriet in the closet, Charlie discovers a letter, purportedly written by him, explaining his absence to Harriet. Rose appears wielding an axe and reveals herself as the Mrs. X killer. She feels that Harriet's husbands are taking her sister from her, motivating her to kill them on their honeymoon night and leave letters behind claiming to be from them, leading Harriet to believe that each husband abandoned her. Charlie flees from Rose. Tony leads the police into the hotel and arrests Harriet, still believing her to be the murderer. Charlie, having been chased to the hotel roof by Rose, gets Tony's attention as they take Harriet away. While the police make their way up to the roof, Rose swings the axe at Charlie and is thrown off the building. Tony catches her, and she is arrested and taken away. Charlie and Harriet resume their lives as a happy couple.

In 2293, retired Starfleet officers James T. Kirk, Montgomery Scott, and Pavel Chekov attend the maiden voyage of the USS Enterprise -B. During the shakedown cruise, the starship is pressed into a rescue mission to save two El-Aurian refugee ships that a massive energy ribbon has snared. Enterprise saves some of the refugees before their ships are destroyed, but becomes trapped by the ribbon, and Kirk goes to a control room to help the ship escape. While Enterprise is freed, Kirk is presumed lost in space and dead after the trailing end of the ribbon tears open the ship's hull. In 2371, the crew of the USS Enterprise -D is in a holodeck computer simulation, celebrating the promotion of shipmate Worf to lieutenant commander. Captain Jean-Luc Picard learns his brother and nephew have been killed in a fire, and is distraught that the Picard family line will end with him. Enterprise receives a distress call from a stellar observatory, where an El-Aurian, Dr. Tolian Soran, launches a probe at the nearby star. The probe causes the star to implode, creating a shockwave that destroys its planetary system. Soran kidnaps Enterprise engineer Geordi La Forge and is transported off the station by a Klingon Bird of Prey belonging to the Duras sisters. Enterprise crewmember Guinan tells Picard that she and Soran were among the El-Aurians rescued in 2293. Soran—who lost his family when their homeworld was destroyed—is obsessed with returning to the energy ribbon to reach the "Nexus", an extra-dimensional realm of wish fulfillment outside normal space-time. Picard and Data determine that Soran, unable to safely fly a ship directly into the ribbon, is altering its path by removing the gravitational effects of nearby stars. Soran plans to destroy another star to bring the ribbon to the planet Veridian III, consequently killing millions on a nearby inhabited planet. Upon entering the Veridian system, Picard offers himself to the Duras sisters in exchange for La Forge but insists on being transported to Soran directly. La Forge is returned to Enterprise, but unwittingly exposes the ship's defense details through the transmitter installed in his VISOR device. The Duras sisters attack, and Enterprise sustains critical damage before destroying the Bird of Prey by triggering its cloaking device, and firing photon torpedoes when its shields drop. When La Forge reports that the starship is about to suffer a warp-core breach as a result of the attack, Commander William Riker evacuates everyone to the forward saucer section of the starship, which separates from the engineering section just before the breach occurs. The resulting shockwave sends the saucer-section crashing onto the surface of Veridian III. Picard fails to stop Soran from launching another probe. The Veridian star's resulting destruction alters the ribbon's course, and Picard and Soran enter the Nexus before the shockwave destroys Veridian III. Picard is surrounded by an idealized family, but realizes it is an illusion. He is met by an "echo" of Guinan left behind in the Nexus. Guinan sends him to meet James T. Kirk, who is safe in the Nexus. Though Kirk is initially entranced by the opportunity the Nexus offers to atone for past regrets, he realizes it lacks danger and excitement. Having learned that they can travel whenever and wherever desired through the Nexus, Picard convinces Kirk to return with him to Veridian III, shortly before Soran launches the probe. Working together, Kirk and Picard distract Soran long enough for Picard to lock the probe in place; it explodes on the launchpad and kills Soran. Kirk is fatally injured in the effort, and Picard buries him at the site. Three Federation starships arrive to retrieve the Enterprise survivors from Veridian III. Picard muses that, given the ship's legacy, the Enterprise -D will not be the last vessel to carry the name.

In the 24th century, Captain Jean-Luc Picard awakens from a nightmare in which he relives his assimilation by the cybernetic Borg six years earlier. He is contacted by Starfleet, who inform him of a new Borg threat against Earth. Concerned that Picard is too emotionally involved with the Borg, Starfleet orders the USS Enterprise to patrol the Neutral Zone in case of Romulan aggression. During their patrol, the Enterprise learns that the fleet is losing the battle against the Borg. Picard and his crew disobey orders and head for Earth, where a single Borg Cube ship holds its own against a group of Starfleet vessels. Enterprise arrives in time to assist the crew of USS Defiant and its commander, the Klingon Worf. Picard takes command of the fleet and directs the surviving ships to concentrate their firepower on a seemingly unimportant point on the Borg ship. The Cube launches a smaller spherical ship towards Earth before being destroyed. Enterprise pursues the sphere into a temporal vortex. As the sphere disappears, Enterprise discovers Earth has been altered—Borg now populate it. Realizing the Borg have used time travel to change the past, Enterprise follows the sphere through the vortex. Enterprise arrives hundreds of years in the past on April 4, 2063, the day before the historic warp drive flight that leads to humanity's first encounter with alien life. The crew surmise that the Borg are trying to prevent first contact and assimilate humanity while the planet is recovering from World War III. After destroying the Borg sphere, an away team transports down to Zefram Cochrane 's warp ship, Phoenix, in Bozeman, Montana. Beverly Crusher and Cochrane's assistant Lily Sloane return to the Enterprise to treat her radiation sickness. Picard and Data also return to the ship after suspecting the Borg have survived their sphere's destruction, leaving Commander William T. Riker on Earth to make sure Phoenix ' s flight proceeds as planned. While in the future Cochrane is seen as a hero, in reality he built the Phoenix for financial gain and is reluctant to be the historic figure the crew describes. A group of Borg invade Enterprise ' s lower decks, assimilating some of the crew and modifying the ship. Picard and a team attempt to reach engineering to disable the Borg with a corrosive gas, but are forced back; the android Data is captured in the melee. A frightened Lily corners Picard with a weapon, but he gains her trust. The two escape the Borg-infested area of the ship by creating a diversion in the holodeck. Picard, Worf, and the ship's navigator, Lieutenant Hawk, travel outside the ship in space suits to stop the Borg from using the navigational deflector to call for reinforcements, but Hawk is assimilated in the process. As the Borg assimilate more decks, Worf suggests destroying the ship, but Picard angrily calls him a coward. Lily confronts the captain and makes him realize he is acting irrationally because of his past with the Borg. Picard apologizes to Worf and orders the activation of the ship's self-destruct and evacuation of the crew to escape pods, while he stays behind to rescue Data. As Cochrane, Riker, and engineer Geordi La Forge prepare to activate the warp drive on Phoenix, Picard discovers that the Borg Queen has grafted human skin onto Data, giving him the sensation of touch he has long desired so that she can obtain the android's encryption codes to the Enterprise computer. Although Picard offers himself to the Borg in exchange for Data's freedom, Data refuses to leave, deactivates the self-destruct, and fires torpedoes at Phoenix. At the last moment, the torpedoes miss, and the Queen discovers that Data has deceived her. The android ruptures a coolant tank, and the corrosive vapor eats away the biological components of the Borg and Data's new skin. With the Borg threat neutralized, Cochrane completes his warp flight. Later that night, the crew watches from a distance as an alien Vulcan ship, attracted by the Phoenix warp test, lands on Earth. Cochrane greets the aliens. Having ensured the correction of the timeline, Picard bids Lily farewell, and the Enterprise crew slips away and returns to the 24th century.

Helen Quilley is sacked from her public relations firm. As she leaves the office building, she drops an earring in the lift, and a man picks it up for her. She rushes downstairs to the London Underground, when a young girl slightly delays her, and the sliding doors shut before she can board the train. Time seems to rewind, and restart, but this time, the girl's mother pulls her child out of Helen's path downstairs, and Helen forces open the nearly closed sliding doors to board the train. Two different versions of Helen continue on with their lives, alternating between two diverging stories. Helen, who boards the train, sits beside James, the man who had picked up her earring in the lift, and they strike up a conversation that cheers her up. She gets home to catch her boyfriend, Gerry, in bed with his American ex-girlfriend, Lydia. Helen leaves him and moves in with her friend Anna. At Anna's suggestion, Helen cuts her hair short and dyes it blonde to make a fresh start. James befriends Helen and she begins to move on from Gerry as he cheers her up and encourages her to start her own small PR firm. They fall in love, despite her reservations about beginning another relationship so soon after her ugly breakup with Gerry. Eventually, Helen discovers that she is pregnant by James. She goes to see him at his office and is stunned to learn from James's secretary that he is married. Having discovered that Helen has learned he is married, James searches frantically for her before finding her on a bridge and explaining that while he is married, he is separated and will soon be divorced, and that he and his wife maintain the appearance of a happy marriage for the sake of his sick mother. After she and James reconcile and declare their love, Helen walks into the road and is hit by a van. Helen, who missed the train, is further delayed by an attempted mugging, which leads to a hospital visit where the cut to her forehead is treated. She arrives home after Lydia has left, and remains oblivious to Gerry's infidelity. Unable to find another PR position, she takes two part-time jobs to pay the bills to support Gerry, who is unemployed and struggling to finish his novel. Gerry continues to juggle the two women in his life, and Helen gradually becomes suspicious. She discovers she is pregnant but does not tell Gerry. Lydia soon realizes Gerry will never leave Helen for her and angrily breaks things off with him, to Gerry's relief. Lydia also realizes she is pregnant by Gerry and summons Helen under the guise of a job interview, but instead reveals the affair and her pregnancy to Helen. Distraught, Helen flees and falls down the stairs. In both timelines, Helen is taken to the hospital and loses her baby. Helen who boarded the train, succumbs to severe injuries and dies with James at her bedside, expressing his gratitude at meeting her on the train. Helen who missed the train recovers and tells Gerry to leave for good. James, who is visiting his mother, picks up Helen's dropped earring in the hospital lift, encouraging her to "Cheer up. You know what the Monty Python boys say..." (the same joke he told Helen in the other timeline), but this time, Helen preempts James, correctly quoting the punch line, " No-one expects the Spanish Inquisition." They turn and gaze at each other.