Lucas blows his first Varsity game and decides to quit the team. The wedge between Nathan and Peyton continues to grow after Peyton tires of Nathan's jabs at Lucas. Meanwhile, Keith forces Karen to deal with her feelings for Dan after she refuses to step foot in the high school gym to support her son.

On the night of Dan and Deb's annual basketball appreciation party stirs up old wounds and new feelings as Karen makes a new friend, Keith faces off with his younger brother once again and Lucas finally makes his move on Peyton. Also, Haley and Nathan grow closer until Brooke spreads a vicious rumor that leaves Haley devastated.

After Whitey cancels basketball practice, Brooke convinces Lucas to let loose and takes him out for a wild night out on the town. Meanwhile, Deb instructs Dan to take Nathan away for a father-son weekend to try and rebuild their relationship, but things don't go exactly as she had hoped.

Aside from a love for hoops, it would seem that Lucas and Nathan are two young men with little in common, but they are bound by the dark secret that they share the same father. Nathan is the star of the high school basketball team and local town hero, while Lucas is the only child of a single working mom. Now the two boys' lives collide when a twist of fate puts Lucas on Nathan's team and the half-brothers compete, not only for control of the court, but also for the heart of Nathan's beautiful girlfriend Peyton.

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.

With the assistance of Peyton and Brooke, Lucas throws Nathan and Haley a wedding reception. Although Haley's parents support the marriage, Deb has a difficult time accepting it. Meanwhile, Dan's recent heart attack causes him to try and mend his relationships with Deb and Lucas.

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...

Keith and Jules' wedding day, and the event has turned the town upside down. Brooke asks Lucas to take her to the wedding as his date, Nathan makes an important decision involving his marriage to Haley, and Jake and Peyton take a big step in their relationship. Meanwhile, Karen and Andy discover Jules' secret relationship with Dan.

Nathan's Uncle Cooper comes into town to take Nathan and Lucas on a racing trip. On the track, Nathan and Lucas are challenged to a race by the beautiful Daytona and her smart aleck brother Jarret, but things go horribly wrong when Nathan loses control of his car and crashes into a wall. Meanwhile, Deb's addiction to pain pills intensifies and Dan exposes Andy's relationship with Karen to his class.

In the second part of the this seamless 2-hour Season Finale of "One Tree Hill," things heat up between Lucas and Brooke since he finally tells her what he feels about her. Nathan and Deb conspire to desert Dan for good, leading to an explosive conclusion when he discovers their plan. Peyton has a shock. Meanwhile, Karen decides to spend the summer holiday in New Zealand. And at the climax of Dan's numerous deceptions someone sets the dealership on fire with him in it.