Season four rose in ratings, averaging 2.9 million viewers weekly, becoming #136 in the Nielsen ratings system.
This season focuses on the final half of senior year at Tree Hill High School.
An emotional Haley confronts Nathan about the sex tape and asks for a list of all his past sexual encounters.
An angry Peyton asks Lucas to skip the dance altogether, but he refuses to take no for an answer.
Karen insists Deb show up for her son's final game and tries to help her get there. After a heart attack, Lucas has a dream in which the spirit of Keith visits and shows him how much one life can affect the lives of others, in a nod to "It's a Wonderful Life".
Haley is the victim of an accident and Dan helps out Nathan. Lucas returns to his everyday life and tries to rekindle his relationship with Peyton.
The residents of Tree Hill must deal with the aftermath of the shocking accident.
Nathan and Rachel are okay while Cooper still remains in a coma.
Peyton and Lucas decide to take their relationship to the next level.Meanwhile, Nathan continues to struggle with memories of the accident.Dan continues to be haunted by remorse over his actions against Keith.Nathan struggles with money problems and reluctantly asks Dan for help.Brooke learns the new man in her life is also her new English teacher. Lucas returns to the Ravens just in time to help the team advance in the playoffs for the state championship.Peyton tries to go back to school, but she breaks down. Nathan is cornered into a no-win situation by Daunte. 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.