Episode: 4×16 (Season 4 Episode 16)
Name: You Call It Madness, But I Call It Love
Originally Aired: May. 02, 2007
Plot: Prom proves to be an unforgettable night for everyone when Lucas realizes who was in the hallway when Keith was killed. Meanwhile, Peyton’s decision to skip Prom leads to a dangerous situation, but also leads to a reconciliation with Brooke. Elsewhere, Nathan and Haley attempt to be romantic teenagers during Prom, but find it hard to do; Dan tries to win over Karen, but as he does so the witness to Keith’s murder closes in on Dan.