: Lucas discovers that Dan, not Jimmy Edwards, killed his uncle Keith during the school shooting in Season 3. This leads to an explosive confrontation on graduation day.
: Brooke and Lucas officially break up after she realizes his growing feelings for Peyton. By the middle of the season, Lucas and Peyton finally begin a serious relationship.
: The series' original finale before the four-year time jump; it features graduation and the births of James Lucas Scott and Lily Roe Scott. Thematic Elements One Tree Hill Season 4 Episodes - TV Guide One Tree Hill - Season 4
: Peyton is targeted by a "Psycho Derek" (Ian Banks), who impersonates her biological half-brother. She eventually meets her actual brother, a Marine also named Derek, who helps her confront her trauma.
: The prom episode featuring the final confrontation with "Psycho Derek". : Lucas discovers that Dan, not Jimmy Edwards,
: The Ravens play for the State Championship; Peyton confesses her feelings to Lucas.
: Deals with the aftermath of the bridge accident involving Nathan, Rachel, and Cooper. By the middle of the season, Lucas and
Season 4 of One Tree Hill (2006–2007) is the final year of high school for the main characters, focusing on the closure of their adolescent lives and the resolution of the series' darkest mysteries. It was the first season to air on The CW network following the merger of The WB and UPN.