After a particularly spectacular basketball game, Lucas quickly supplants Nathan as the team's most popular player.
Lucas and Nathan bear the brunt of Dan's abuse as he coaches them into the playoffs, pushing both of them to their emotional breaking points.
Brooke's smug new male neighbor rescues her after she is arrested for shoplifting. Nathan and Haley have their first post-wedding argument when he buys her a gift rather than a much-needed car. Lucas' attempt to help Dan with rehab ends in disaster after Dan reverts to his old ways. Peyton tries to organize a club that caters to both kids and adults, but in order to finalize her pet project, she is pressured to try cocaine.
On the first day of senior year, estranged spouses Nathan and Haley have trouble adjusting as classmates. While Brooke continues to play hard-to-get, Lucas learns a troubling secret about Peyton's mom. Meanwhile, Dan starts to uncover the truth about the dealership fire.
The aftermath of the school shooting forces the residents of Tree Hill to examine their lives. Nathan reassesses his relationship with Haley, while Brooke and Rachel (recurring guest star Danneel Harris) join forces to heal the student body. Dan must deal with the ramifications of shooting Keith. And Lucas and Peyton consider the implications of their kiss in the library.
