One Tree Hill

The aftermath of the post-wedding car accident unfolds. While Haley is deeply affected by Nathan's rescue attempt, Brooke confronts Lucas, and Peyton makes a startling discovery.

As the lives of Nathan, Rachel and Cooper remain turbulent following the car accident, Brooke celebrates her 18th birthday but finds it diminished by her struggles with Peyton.

Lucas and Brooke, now broken up, clash at a post-game party, and Haley realizes that Rachel is plotting to seduce Nathan.

Peyton introduces hip-hop sensation Lupe Fiasco at the nightclub Tric, while rumors that Brooke is pregnant run rampant. Still dealing with the car accident, Nathan buys a motorcycle, despite Haley's reservations.

When Lucas discovers that newcomer Derek's interest in Peyton is more than brotherly, Derek becomes menacing. Haley feels Nathan slipping away after he receives a scholarship offer to attend Duke University.

Nathan approaches Dan for help with his and Haley's finances. Despite his heart condition, Lucas rejoins the Ravens, teaming with Skills.

Brooke copes with the T.A.R.T. fashion show and a new boyfriend. Rachel makes the cover of Maxim magazine, causing chaos at Tree Hill High.

Derek convinces Peyton to take a chance with Lucas -- but, at the same time, Brooke is approaching Lucas about getting back together.

As Whitey's last game approaches, the residents of Tree Hill feel the pressure of a looming state championship showdown. Meanwhile, Peyton reveals to Lucas that she has feelings for him.

Lucas receives an unlikely visitor: his supposedly dead uncle, Keith. Meanwhile, the lives of Haley and her unborn child are threatened when she experiences serious complications with her pregnancy.

Following his heart attack, Lucas returns to school, hoping to rekindle his romance with Peyton. Haley learns that Nathan was responsible for her accident.

With senior prom only weeks away, Haley's frustration over her injuries increases. Skills and Mouth try to help Nathan earn money for the big dance by stripping.

A class assignment reveals the deepest secrets and desires of Lucas and the students of Tree Hill High. Worried about college prospects, Skills turns to Haley.

Haley confronts Brooke regarding the stolen calculus test. Meanwhile, Lucas and Peyton consider taking their relationship to the next level.

On the day of the prom, everyone in Tree Hill experiences the repercussions of Nathan's pre-prom party. Haley asks Nathan for a list of his past sexual conquests.

Lucas discovers who witnessed his uncle's killing a year ago. Meanwhile, Peyton's decision not to attend the prom leads to dire consequences.

In an episode shot on location in Honey Grove, Texas as part of a national contest, the teens of Tree Hill mount a rescue mission to save Mouth from his ill-advised road trip with Rachel.

Nathan fears for his future as past mistakes come back to haunt him and Haley. Lucas hears a shocking confession after making contact with the mysterious witness to the murder of his uncle.

Nathan and Haley grow closer, despite the recent scandal. Brooke wonders if a spark might be rekindled with Chase.

As graduation day at Tree Hill finally arrives, Brooke's guilty conscience prompts her to make an important decision, while Haley prepares her valedictorian speech.

In the powerful fourth season finale, the Tree Hill High School graduates share their bittersweet, final moments together. At the same time, both Karen and Haley go into labor, while their loved ones stand by.