Nathan Scott is Tree Hill High's biggest basketball star and is dating Peyton, a cheerleader. Nathan's half brother, Lucas, joins the team - and threatens to take both Nathan's spot in the lineup and his girl.

The knowledge that Dan actually requested joint custody over Lucas but was turned away by Karen makes Keith doubt her and the Scott boys, who now train together as friends, how their lives would have been growing up as brothers. Peyton and Brooke lose Jake's baby daughter Jenny in the mall, and find Nikki picked her up. Haley is furious when she finds porn sites on Nathans computer, even though everybody else considers cyber-sex innocent fun, no competition for her. Since coach Whitey must have an operation, Dan manages -to his fury- to be made Ravens coach for one match, and works the boys like a penal company. Jake thinks he'll lose a custody battle against Nikki, so he considers moving to family in Savannah and gets Peytons support. Lucas comes to a decision which worries both Karen and Keith.

After the prom, Anna sleeps over at Peyton's- Felix sneers she's getting a worse reputation then his, while Peyton has a hard time with lesbianism-innuendos, even though Brooke says that appeals to boys, but ends up making a stand at school. Brooke finds Nathan slept on Lucas's floor; when he goes home, Haley tells him she respects his sacrifice and wants him to go to Highflyers, but won't do the one thing he asks, stop seeing Chris, so he walks out again and warns Chris in ominous terms and grip. Brooke blames Felix for her broken windshield and rages at him; he finds out it was Mouth, who also tells Lucas, but pays anyway; in the end he convinces her of his love. Dan takes the reins back at the dealership and offers Keith to stay on. Karen orders Lucas to take the medical test, or no basketball anyway- Nathan confesses he told her. Chris gets a chance to make a tour, asks Haley along and kisses her again. After Deb confesses her infidelity with him to Karen, Jules gets a call from Keith he loves her, and reports it to Dan

Deb is angry to hear from Dan Lucas moves in, but hopeful now Haley has left Nathan he might also return. Nathan is a wreck, and seems determined to wreck his school-prospects; he won't listen to anyone, even hits the still taunting Dan. Jake and Jenny live in Peyton's room, but she is reluctant to become intimate again. Erica stops at nothing to defeat Brooke, but clever speeches by her and Mouth still turn the tide. Lucas seems to feel at home with Dan.

Niki turns up with a court decision in absentia awarding her custody of Jenny- Andy offers Jake legal help as fleeing is losing. Lucas goes to his ma now the truth is out but decides to stay with Dan as he considers himself the enemy's only weak spot. Keith feels betrayed by everyone; Dan can't resist gloriously admitting having set him up and is physically assaulted. Brooke dreads her impeding departure and realizes she may stay with a friend; Peyton is willing, but her parents refuse. Anna turns Felix in to the principal for writing dike on Peyton's locker, with disastrous results: he is dumped by Brooke, his parents send him to military school, and Anna even blames him for not knowing she's the lesbian. Nathan drives to where Haley tours, pours out his heart ready to do everything for their marriage, but only hears she wasn't ready and right now the show comes first, so he returns. Lucas makes Brookes year: Karen and he take her in. Keith leaves, anywhere and maybe forever.

Last year's time-capsule is maliciously opened 49 years early, revealing many kids' embarrassing secrets, lies and even worse truths, shown on TV screens at school and even on the Internet. Peyton prepares a benefit for the National Breast-cancer action, in memory of her recently deceased ma Ellie Harp; it rocks and brings most kids back together. Keith announces his engagement to Karen and his plan to adopt Lucas. Jimmy Edwards, who bagged the worst on everyone in his time-capsule speech, gets roughed up, but the Scott brothers, Mouth and Rachel save his bacon. Dan reminds Keith how close they were as boys and hands him the black ledger but is scorned and burns it. Nathan and Haley enjoy closeness again. Lucas embraces Keith as his future father, without step-.

A dangerous day at Tree Hill High gives Nathan and Lucas a common goal, as they put their lives on the line to save their friends when a distraught student comes to school with a gun and holds Haley hostage.

The aftermath of the school shooting and the death of Jimmy Edwards forces everyone in Tree Hill to examine their lives. Nathan reassesses his relationship with Haley, while Brooke and Rachel join forces to heal the student body. Dan must deal with the ramifications of shooting Keith, while Lucas and Peyton consider the implications of their kiss in the library.

Peyton finally realizes that her brother Derek isn't her real brother but in fact the very same person that's been sending her online messages using the alias "watchmewatchyou". When she learns this and starts pushing him away, Derek breaks into her house and tries to hurt her. She is saved in the last minute by her real brother Derek and Lucas. In the end, Derek disappears after surviving a bad fall through Peyton's window.

Brooke has her hands full with her model for the T.A.R.T. fashion show and a new boyfriend. Rachel makes the cover of "Maxim," causing chaos at Tree Hill High. Meanwhile, Lucas learns of Nathan's dealings with Daunte, and ultimately has to choose between Nathan and his love for basketball. Haley takes on a babysitting job only to find herself in over her head and Peyton's half-brother, Derek, forces her to confront her deepest fears.

Derek convinces Peyton to take a chance with Lucas at the same time that Brooke approaches him about getting back together. Daunte's latest demand leads Nathan to seek help from an unlikely source - Dan. When Rachel learns of a failing grade, she turns to Haley for tutoring. Nathan is named MVP of the Ravens at the annual sports banquet.

Following his heart attack, Lucas returns to school, hoping to rekindle his romance with Peyton. Haley learns that Nathan was responsible for her accident. Brooke and Rachel hatch a plan to steal the next calculus exam, while Dan faces murder charges and Deb breaks out of rehab.

With senior prom only weeks away, Haley's frustration over her injuries increases and Skills and Mouth hatch a plan to help Nathan earn money for the big dance by stripping. Brooke betrays Rachel in order to get closer to a new guy and Peyton and Lucas resolve to be happy. Struggling with her drug addiction, Deb makes a choice that could end her life.

Haley confronts Brooke regarding the stolen calculus test. Lucas and Peyton consider taking their relationship to the next level as Peyton and Brooke grow closer. In Deb's absence, Nathan throws a senior party at the Scott House, where a sex tape from Nathan's past surfaces.

It will be an unforgettable Prom at Tree Hill High when Lucas discovers who was in the hallway when Keith was killed. Meanwhile, Peyton's decision to skip Prom leads to dire consequences. Nathan and Haley vow to be romantic teenagers at Prom, while Dan tries to win Karen's affections, as the witness to his murder closes in.

Nathan and Haley grow closer in spite of the recent scandal. Brooke wonders if a spark might be rekindled with Chase. Peyton receives a tempting offer that would ultimately take her away from Tree Hill. Mouth reconnects with Gigi, while Lucas tells Karen that Dan is a murderer, setting off an explosive series of events.

As graduation day dawns in Tree Hill, some dreams begin as others end. Haley prepares for her graduation speech and her role as a young mother, while Nathan prepares for life without basketball. Brooke makes a heartfelt confession that puts her future in jeopardy. Lucas confronts Dan as Karen's life is threatened.

Nathan's depression hits rock-bottom, to the point of ignoring Jamie, so Hayley warns she may leave him. Uncle Lucas steps in as father figure when Jamie enters a go cart competition. Lucas takes the coach job for his high-school team the Ravens, assisted by Skills, but most promising player Quentin Fields is an arrogant idiot, who must be suspended due to his misbehavior in Hayley's class. Nathan nearly drowns himself but hen decides to pick himself up for Jamie's sake. Brooke decides to invest in a record label for house-mate Peyton to run. Nathan and Hayley hire a foxy nanny.