The gang hits the road to Charlotte where Brooke is determined to win first place at the annual cheerleading competition, but when one of her squad falls ill, Peyton begs Haley to step into the cheerleader's shoes for a day. Meanwhile, after Whitey assigns Lucas and Nathan to the same room, tempers flare and Haley is caught in the middle.

Lucas must make a difficult decision regarding Brooke. Haley considers having sex with Nathan.

Lucas is shocked to learn that Dan once asked Karen for joint custody of Lucas when he was a baby. Meanwhile, Peyton panics after Nicki kidnaps Jake’s baby while she is babysitting.

After Lucas and Keith learn that Dan had a heart attack and is still in the hospital, they decide it is best for them to return to Tree Hill. When Deb learns about Haley and Nathan's marriage, she grows hostile. Meanwhile, angry that Lucas left Tree Hill without saying goodbye, Peyton and Brooke try to mend their friendship.

The opening of Karen's club "Tric" brings together the people of Tree Hill. Lucas and Felix come to blows over Anna. After Chris quits his gig the night of the club opening, Haley must face her fear of performing to save the night for Peyton. Although Mouth tends to Brooke while she is drunk, Felix sneaks in and attempts to take the credit. Keith and Jules realize their relationship has reached a new level, while Dan deliberately tells Karen that Deb slept with Keith.

Lucas takes Anna to the formal night but by the end of the night ends up with Brooke. After spending time with Chris, Haley arrives late to the formal which angers Nathan. Meanwhile, Peyton struggles with pressure to do drugs.

Nathan is concerned about Lucas' health, so he tells Karen that Lucas didn't take the heart test. Dan offers Keith to continue working at the dealership-as vice president. At school, Peyton must confront the rumors going around that she is a lesbian. This affects her friendship with Anna. As for Nathan and Haley, they begin to grow apart...

When Tree Hill High does a time capsule project, the gang confesses their most intimate secrets to an anonymous video camera. Nathan's anger over Haley's absence continues to grow, landing both Lucas and Nathan in jail. Peyton and Jake's feelings for each other heat up, while Felix throws Brooke a party to celebrate her new gig as student body president. Meanwhile, when brought to court, Lucas opts to live with Dan and Deb rather than Karen.

Lucas attempts to play in the first game after Keith's death, but cannot bring himself to do it; Nathan and Haley prepare to renew their vows, while Mouth tries to get closer to Rachel; Peyton receives a surprising offer; and Brooke finds a way to get revenge on Rachel.

The residents of Tree Hill must deal with the aftermath of the shocking accident that left everyone without words. In the midst of all the chaos, Dan extends his help to Karen now that she is pregnant, Lucas and Peyton's friendship continues to grow stronger, and once rivals Brooke and Rachel move past their differences and manage to become good friends. Brooke has a difficult decision to make about her relationship with Lucas and Skills decides to try out for the Ravens.

It's her eighteenth birthday, but Brooke soon realizes that she has no one but Rachel to celebrate it with. Meanwhile, Nathan continues to struggle with memories of the accident and Dan continues to be haunted by remorse over his actions against Keith.

Peyton spends more time getting to know her newfound brother, Derek. Meanwhile, Lucas gives up on his love for Brooke and Rachel tries to start a romance with Nathan.

Rumor surfaces that Brooke might be pregnant, causing Karen to worry as she fears that the baby might be Lucas'. Meanwhile, Rachel continues to get closer to Nathan when she confesses that she saw Keith during the accident.

The aftermath of the series of unfortunate events at Tree Hill begins. Lucas returns to his everyday life, following his heart attack, and tries to rekindle his relationship with Peyton. However, things are rougher for Haley when she discovers that Nathan had more involvement in her accident than she could have ever imagined.

A class assignment reveals the deepest secrets and desires of Lucas and the students at Tree Hill High. Worried about college prospects, Skills turns to Haley, while Nathan wrestles with Deb's suicide attempt. Chase learns that Brooke cheated on her calculus exam, while nudity and drugs run rampant in the halls of the school.

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's Prom day, and emotions are flying high at Tree Hill. An emotional Haley confronts Nathan about the sex tape and asks for a list of all his past sexual encounters. Meanwhile, an angry Peyton asks Lucas to skip the dance altogether, but he refuses to take no for an answer. Finally, Brooke and Peyton let out all their tension in a confrontation that can tear them apart forever.

It's Prom night, but things start to go awry as Lucas discovers who was the person in the hallway when Keith was killed, and psycho Derek holds Peyton hostage at her own house. Meanwhile, Haley and Nathan vow to be romantic with each other throughout the night, and Dan continues to win over Karen's affections.

When Mouth and Rachel's road trip goes wrong, the other teens go out to their rescue. While on the trip, Nathan and Haley get a second chance to enjoy their Prom and Peyton and Lucas decide to take their relationship to the next level. Finally, Brooke reveals the truth about the stolen calculus exam to Haley.

Brooke and Peyton finally rekindle their friendship, Nathan's past mistakes continue to haunt him and Haley, and Lucas hears a shocking confession from the witness to Keith's murder.

As the end of the school year approaches, Peyton considers participating in a music internship in Los Angeles, while Brooke tries to reconnect with Chase through yearbook signatures, and Haley struggles to write her valedictorian speech. Meanwhile, Dan suggests that Lucas get professional help when Karen worries about his obsession with theories about Keith's murder.

As graduation approaches, Haley prepares for the recital of her valedictorian speech and motherhood. Nathan must adjust to life without basketball, while Brooke makes a confession that may have great consequences. Lucas confronts Dan after Karen's life is threatened.

It's confrontation time in Tree Hill, as Lucas confronts Peyton about her nasty behavior towards Lindsey and Brooke must confront Victoria about meddling with Peyton's record label. Meanwhile, Nathan begins to grow closer to Carrie, Haley continues to struggle in dealing with Quentin, and Mouth must choose sides between his co-workers and Alice.

The Honorary Title performs at Tric and Mia plays her song there as well. Carrie tries to get closer to Nathan. Brooke sets Mouth up on a blind date with her assistant and Lindsey confronts Lucas about Peyton.

Brooke continues to pursue Owen. Haley sees something happening in Peyton's office. Quentin needs to change his negative approach in order to succeed in the season-opening game. Mouth tries to win Millicent back.

Haley, Brooke, Peyton, Lindsey and Mia get locked in the Tree Hill High library on the night of the Ravens' first game. Also Brooke tries to stand up for her mother, while Lucas and Nathan discuss whether to tell their loved ones about their indiscretions.

Brooke runs into someone from her past while on a trip to New York with the Tric bartender, Owen. Nathan and Lucas attend Dan's hearing while they try to protect Jamie from him. Mia gets an offer from a major record label and in the meantime, Haley and Nathan's marriage is on the rocks.

On the eve of Lucas and Lindsey's wedding, they conspire to save Nathan and Haley's marriage. Brooke pairs Peyton with an old boyfriend, while Rachel and Dan return to Tree Hill.

On Lucas and Lindsey's wedding day, Peyton must choose between intervening and losing Lucas forever. Nathan uses the event to try to mend his marriage to Haley. All are shocked when Dan, who is out of prison on parole, shows up at the event.