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.

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.

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.

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 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.

Dan must face the harsh consequences of his decision to murder Keith as Karen and Haley's pregnancies complicate the lives of Nathan and the graduating seniors of Tree Hill High. Lucas wrestles with his post-high school options, and Peyton and Brooke prepare to spend the summer in Los Angeles together.

It's four years into the future and the Tree Hill gang has finished college. Now, their lives have taken completely different directions. Lucas has written and published a book, Brooke has made it big in the fashion industry with her brand "Clothes Over Bro's", Peyton is pursuing a career in the music business, and Nathan and Haley continue to raise a now older James.

In this flashback episode, memories are looked back upon. Lucas surprises Peyton in Los Angeles and they talk. He asks her something and is left with a surprising answer. Meanwhile, Nathan's temper triggers up after a guy reminds him of his cheating in high school basketball games.

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.

Lucas picks up the pieces after being left at the altar by Lindsey, while Nathan and Haley deal with the repercussions of Jamie's abduction. Dan is free for now, but he must find himself a job to convince the parole that he is changed for good. Brooke is haunted by her past as a woman from adopting asks her questions, while Peyton gets a visit from an old friend.

Lucas is crushed by devastating news. Quentin is pushed to his limits during a Ravens game. Dan's is second on the donor recipient list to get a new heart. Haley thinks about her decision to release a new album while Brooke's baby undergoes emergency surgery and a shocking truth stuns Peyton, told by Lucas.