It's the first day of senior year and estranged spouses Nathan (James Lafferty) and Haley (Bethany Joy Lenz) have trouble adjusting as classmates. While Brooke (Sophia Bush) continues to play hard-to-get, Lucas (Chad Michael Murray) learns a troubling secret about Peyton's (Hilarie Burton) mom. Meanwhile, Dan (Paul Johansson) closes in on the truth about the dealership fire.