In 1993, Jeanette Turner bumps into popular Kate Wallis and her boyfriend, Jamie Henson, at the mall where Jeanette and her friends Mallory Higgins and Vince Fuller create a bucket list of daring activities to challenge each other. While playing hide-and-seek in a house her father Greg recently sold, Jeanette meets Martin Harris, the house's new owner and Skylin High's new vice principal.

In 1994, Kate has been missing for a year, and the now-popular Jeanette celebrates her birthday with Kate's friends and Jamie, her now-boyfriend. A jealous Mallory confronts Jeanette for taking over Kate's life, which Jeanette dismisses. When it is announced that Kate has been found alive, Jeanette runs to see Jamie, who punches her in the face for what she did.

In 1993, Jeanette, Mallory, and Vince meet Jamie's best friend Ben who offers advice on a prank the trio are planning. Kate believes her stepfather Rod is cheating on her mother, Joy. She tells Joy and attempts to find proof but discovers Rod is only planning a surprise cruise. Kate apologizes to Joy, who berates Kate for making accusations and being an embarrassment. Upset, Kate leaves the party and gets drunk. The gardener Scott returns Kate home where she later discovers Joy and Scott are having an affair. Distressed, Kate sneaks out again and is found and abducted by Martin Harris.

In 1994, Jamie – who has reconciled with Kate – and Rod are worried that Kate refuses to talk to the police or go to therapy. Jamie secretly meets with Jeanette, who swears she is innocent and begs Jamie to believe her; the two kiss as Kate secretly watches. Angry, Kate goes to the police and offers Jeanette's necklace into evidence as proof of her accusation.

In 1993, Mallory is furious when Jeanette flushes the stash of joints that Mallory pilfered from her mother. Cindy suggests Jeanette distance herself from Mallory, recalling her own high school popularity and friendship/rivalry with Kate's mother. Jeanette instead sneaks over to Martin Harris' house to steal an old yearbook as an apology gift for Mallory.

In 1994, Greg and Derek furiously confront Jamie for punching Jeanette. Jeanette is questioned by the police and is shocked when they produce her necklace. Cindy begins to doubt Jeanette. Vince meets up with Ben, whom he is secretly dating. Jamie asks Jeanette to keep their kiss a secret and asks how she seemingly knew Kate went missing before everyone else did.

In 1993, Kate attempts to bond with her step-sister Ash as the family prepares for their annual hunting trip. Kate tries to confide in Ash about Joy's affair, but Ash brushes her off before she's able to. Kate abandons a date with Jamie in favor of stargazing with Martin.

In 1994, Kate attends therapy where she meets Mallory; the two bond over their mutual hatred of Jeanette. The police tell Kate and Joy that they do not have a solid case against Jeanette, as fingerprints on necklace were inconclusive. Ash attempts to bond with Kate, but Kate blames Ash for driving her to confide in Martin. After Derek jokes that Ash should assume an alter ego to reach Kate, Ash joins Kate's abduction victims' chatroom under an alias.

In 1993, Jeanette attends a date at the carnival with dorky out-of-towner Gideon but abandons him after people make fun of them. Martin later scolds her. Kate and Martin continue to bond, then steals her left-behind scrunchie when she leaves. When Jeanette notices, she offers to return it to Kate and takes it from him.

In 1994, Kate confronts Jamie about his kiss with Jeanette, but he accuses her of making it up. When he attempts to gaslight her by blaming her post-traumatic shaky memory, she breaks up with him. Jeanette and Derek attend the carnival in hopes of talking things out with Kate, while Cindy starts to descend into alcoholism. Greg meets Angela at a video store. After Jeanette chases Kate and Mallory into a mirror maze, Derek tells her she should go back to being her old self, but Jeanette says she cannot.

In 1993, Jeanette, Mallory, and Vince shoplift as Tenille's mother Tanya flirts with Martin. Jeanette covers for Vince and goes to "mall jail", where she bonds with Jamie. Later, Jeanette sneaks into Martin's house. When Martin and Tanya return, Jeanette hides in a closet. Jeanette witnesses Tanya confiding in Martin in an attempt to seduce him. Tanya discovers Jeanette in the closet and allows Jeanette to leave without telling Martin.

In 1994, Greg and Cindy argue as Derek prepares to go to college. Cindy snoops around Jeanette's room and finds Martin's house key. When Greg and Derek both belittle her concerns, Cindy leaves to stay with her sister. Later, Jeanette catches a near-kiss between Vince and Ben at the video store; while Tanya gives an interview where she paints Martin, instead of herself, as the aggressor while recounting their date. Greg, to his disappointment, confirms the key Cindy found in Jeanette's room is Martin's house key.

In 1993, Kate is uneasy when Jamie gifts her a promise ring. Jamie gets drunk at the mall with Kate and her friends, and the two accept a ride from Martin. When Kate arrives to her birthday dinner celebration late, a furious Joy tells her she already told everyone to go home. Kate reveals Joy's affair to Rod, and Joy slaps Kate. Devastated, Kate runs away to Martin's house.

In 1994, Kate is unable to eat or sleep. After inviting Mallory over for the first time and disclosing this to her, the two get high along with Ash. Joy pressures a reluctant Kate to go on a talk show to which she later agrees after a random girl claims Martin had once tried to abduct her too.

In 1993, Vince and Jeanette abandon their posts to keep watch while Mallory plays a prank video school-wide. Jeanette overhears a meeting between Martin and Joy where Joy discloses that Kate never came home the previous night. After Mallory is caught and her video confiscated by Martin, she angrily confronts Jeanette, who breaks off their friendship. Martin destroys the confiscated tape because it shows Kate in his house's window momentarily.

In 1994, Greg questions Jeanette about the key to Martin's house and forces her to give it to the police. Jeanette tries to pull away from Vince in order to protect his secret relationship with Ben and soon decides to drop out of school to avoid scrutiny. A drunken Jamie is arrested after accidentally crashing his car while driving Ben, leaving Ben with a serious arm injury.

In 1993, Martin leaves Kate at his house where she stays the day instead of going to school. After Kate is designated a missing person, Martin worries and tells her to go, but the two procrastinate instead by playing Never Have I Ever. After twenty-one days together, the two have started a romantic relationship under the mutual agreement Kate must not leave his house. Halloween and Thanksgiving pass, and on Christmas Eve Kate has fallen into a depressive state as she misses the outside world. That night, Jeanette sneaks into Martin's house while he is out shopping and steals a snow globe (the one in Mallory's possession in 1995) but accidentally drops her necklace, which Kate picks up and keeps secret from Martin. Kate later sneaks out to spy on her parents and leaves with the assumption they are enjoying their lives without her. The following night, Kate attempts to leave for good but Martin locks her in the basement to protect his reputation.

In 1993, Mallory confronts Jeanette at her home over stealing Martin's snow globe. Jeanette gives her the snow globe and kicks her out of the house.

In 1994, Jeanette again breaks into Martin's house and hears Kate calling for help from the basement but ignores her pleas. Kate does not realize Jeanette heard her.

In summer 1999, a reluctant Megan Landry, her sister, Lily, and their mother, Debby, welcome exchange student Isabella LaRue. Megan shows Isabella around town before Megan's best friend, Luke Chambers, introduces Isabella to their friend group and invites her to a party at the lake during an annual bioluminescence event. Isabella asks Megan's permission to hook up with Luke to which Megan agrees (though immediately regrets).

In winter 1999, Megan, now dating Luke and best friends with Isabella, receives a scholarship to University of Washington. Debby and her coworker Steve (who is also Luke's father) are dating as well. While hooking up at the Chambers' cabin, Megan and Luke witness a local conspiracy theorist shooting a gun in the woods. At the Chambers' Christmas party, a video of Isabella and Luke having sex is played. Megan storms out, heartbroken.

In summer 1999, Isabella writes to her boarding school roommate, Lisa. Isabella convinces Luke to throw a party at his pool. Attendees include Brent, Luke's older brother, Parker, Brent's girlfriend, and Jeff, a boy filming everything with his video camera. Isabella and Megan agree to find a way to tolerate each other before Isabella and Luke kiss.

In winter 1999, Isabella is put on probation at school for the video, but it's revealed it was actually Megan in the video and Isabella is taking the fall to protect Megan's scholarship. The two burn the video tape and plan to find out who played it at the party. Suspecting Brent, Isabella and Parker break into the Chambers household and steal all their video tapes. Upset after overhearing Megan call Luke the most important person in her life, Isabella tells Debby there's something she should know.

In winter 1999, Megan is upset that Isabella confessed to Debbie that it was actually Megan on the tape, and they get into an argument about loyalty. Meanwhile, a box of the tapes is mysteriously dropped off at the sheriff's office, showing Brent having filmed sex with minors, but managed to avoid the any punishment from the law as his father gets it swept under the rug. Megan and Isabella discover that Jeff knows about Megan being on the tape, and decide to blackmail him for his silence.

In summer 1999, Megan and Jeff create fake IDs so that they, along with Luke and Isabella, can go to a bar. Megan and Isabella gain entrance, though Jeff and Luke have to wait outside before Sheriff Myer discovers them. Hanging out at the Chambers', Luke kisses Isabella out of jealousy after seeing Jeff and Megan kissing.

In winter 1999, Megan's ceiling begins leaking and the Landrys, along with Isabella, attempt to stay with the Chambers. However, at dinner, Brent's behavior, along with the fact that Steve got Myer to drop the charges against them, creates a rift between Steve and Debbie. Isabella offers a share of $5000 for the repairs, but Megan declines.

In summer 1999, Isabella writes another letter to her best friend Lisa and is shaken by the unexpected arrival of Trevor, her former lover and Lisa's brother. Tagging along to a Christmas in July party, Trevor realizes that Isabella has not told Megan about what happened in St. Barts before her arrival. Isabella attempts to seduce Trevor when confronted, but he rebuffs and leaves. Afterward, Isabella and Luke have sex at the Cabin, though later she discovers Megan has feelings for him, and decides to break up telling Megan she is not ready for a serious relationship.

In winter 1999, Isabellas gift to Megan gains more resentment at Isabella for social status. Megan goes to Ned and agrees to do a job for him. Debbie discovers Isabella's unsent letters to Lisa, to which Isabella responds by saying that her friend is "patient".

In summer 1999, Megan plans a party for Luke's 17th birthday and learns that Isabella dumped him the night before. Later at the party, Megan is dumped by Jeff.

In winter 1999, Megan prepares to spend a day with Isabella and Luke at "The Plunge", but bails last minute to work for Ned at his home. After jumping into the ice cold lake and sharing a towel, Luke kisses Isabella, but she backs away out of respect for her and Megan's friendship. After returning from Ned's, Megan has sex with Luke, who lies to her by claiming that Isabella tried to kiss him.

In winter 1999, Megan is still upset that Isabella kissed Luke and did not tell her. In an effort to save a New Year's party, Luke takes the keys to an abandoned property that his father owns. Megan learns she is pregnant. At the party, she confronts Isabella, who reveals that Luke was the one who kissed Isabella. When Megan goes to talk to Luke, she finds him bragging about cheating on Megan. After speaking to Isabella, they plan their revenge on Luke, with Megan luring him to Luke's family's cabin.

In summer 1999, Megan and Luke have sex together for the first time while Isabella goes to the high school car wash. There, she overhears Brent talking about making sex tapes before he makes a lewd pass at her, despite Steve witnessing, and condoning.

In winter 1999, Megan traps Luke at the cabin as she and Isabella drug him and coerce him into confessing his misconduct. He confesses to making the sex tape, but does not know who exposed it at the party before putting Isabella on the spot for having sex with him once before he and Megan got together. Enraged, Isabella takes out a gun and shoots at him.

In October 1999, Luke announces his plan to join the Coast Guard Academy instead of attending Branson, much to his father's disappointment. In November, Brent and his friends harass Luke saying he does not have the courage to make a sex tape. In December, Luke tells Steve of his acceptance into both Branson and the Coast Guard Academy, angering Steve. At the Christmas party, after Steve threatens Luke into attending Branson, a frustrated Luke has an employee play his sex tape with Megan at the party. His relationship with Megan becomes strained.

In January 2000, the unknown figure is revealed to be Brent. After an argument, Brent pushes Luke into the lake, where he apparently drowns. Steve looks for a way to cover this up as Megan and Isabella hide their involvement with Luke's disappearance. Megan puts up missing person fliers and later gets into an argument with Isabella resulting in her breaking off the friendship.