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.

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 finds herself frustrated over her injuries while Skills and Mouth help Nathan find a job as a stripper in order to earn money for the senior prom. Meanwhile, Brooke betrays Rachel in order to get with a new guy and Lucas and Peyton finally reach happiness in their relationship.

A class assignment reveals the deepest secrets and desires of Lucas and the students at Tree Hill High. Worried about college prospects, Skills turns to Haley, while Nathan wrestles with Deb's suicide attempt. Chase learns that Brooke cheated on her calculus exam, while nudity and drugs run rampant in the halls of the school.

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.

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.