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.

Nathan gets two surprises in a row, and everyone is eager to share their advice with him. Deb also shares something she picked up. Brooke decides to celebrate while Peyton is being attacked by her stalker.

Nathan struggles with money problems and reluctantly asks Dan for help. Elsewhere Brooke learns the new man in her life is also her new English teacher. Peyton gets help from an unexpected source, and Lucas returns to the Ravens just in time to help the team advance in the playoffs for the state championship.

Peyton returns to school, but she breaks down. In the meantime Nathan is cornered into a no-win situation by Daunte. Brooke's fashions are a hit at the local show. And Deb takes drastic action for her addiction.

Derek tells Peyton to give Lucas a chance just as Brooke tries to make up with him. Rachel asks Haley to tutor her when she discovers she is failing a class. And Nathan has more trouble with Daunte.

As the Ravens prepare for the championship, Lucas learns Nathan intends to throw the game and decides on a risky plan to even the odds. Karen insists Deb show up for her son's final game and tries to help her get there. Also Dan makes a last plea with Daunte.

After a cardiac incident, Lucas has a dream in which the spirit of Keith visits and shows him how much one life can affect the lives of others, with a nod to “It's a Wonderful Life.” Elsewhere, Hayley is the victim of an accident and Dan helps out Nathan.

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.