A dangerous day at Tree Hill High gives Nathan and Lucas a common goal, as they put their lives on the line to save their friends when a distraught student comes to school with a gun and holds Haley hostage.

The aftermath of the school shooting and the death of Jimmy Edwards forces everyone in Tree Hill to examine their lives. Nathan reassesses his relationship with Haley, while Brooke and Rachel join forces to heal the student body. Dan must deal with the ramifications of shooting Keith, while Lucas and Peyton consider the implications of their kiss in the library.

Nathan and Haley grow closer in spite of the recent scandal. Brooke wonders if a spark might be rekindled with Chase. Peyton receives a tempting offer that would ultimately take her away from Tree Hill. Mouth reconnects with Gigi, while Lucas tells Karen that Dan is a murderer, setting off an explosive series of events.

Victoria bails Millicent out of jail the morning after her arrest and tells her to get herself together before she shows herself again. But Victoria is doubtful that Millicent has learned her lesson and proceeds to keep an eye on her and she is proved correct when Millicent steals a dress from Brooke's new collection to give to her model friend Makenna is exchange for a packet of blow. Mouth is distraught at the change in Millicent and they break up. Clay tries in vain to hold onto his one client but it is not to be and so he packs up his apartment much to Quinn's dismay. Nathan is told by his agents that he won't play NBA this season and his only option is to play in Spain and be ready for the next season but this move coincides with Haley's planned record tour of the US. Skills records a video with the help of Jamie for a new job in L.A. Elsewhere, Julian mistakenly tells Alex that Brooke cannot have children which further deepens the rift between Brooke and Julian after Alex tries in her own way to help Brooke. Despondent after being told to stay away from Julian Alex slits her wrists in the bath and leaves Julian a voice-mail telling him she won't bother him anymore.