It will be an unforgettable Prom at Tree Hill High when Lucas (Chad Michael Murray) discovers who was in the hallway when Keith (Craig Sheffer, who does not appear in the episode) was killed.

Meanwhile, Peyton's (Hilarie Burton) decision to skip Prom leads to dire consequences. Nathan (James Lafferty) and Haley (Bethany Joy Galoetti) vow to be romantic teenagers at Prom, while Dan (Paul Johansson) tries to win Karen's (Moira Kelly) affections, as the witness to his murder closes in.