Haley turned up at Nathans door, asking to be together again, but he is urgently called away to the fire in Dan's office- Deb asks her along. Peyton tells Lucas about Elisabeth who claims to be her -dead- mother but knows things; her dad now says her beloved ma was not her biological mother- she turns away from both. Three months later Brooke returns walking straight up to Lucas, who was however just waiting for Karen. Nathan finally can go to High Flyers, and Haley's declaration of 'never ceased' love doesn't get to him; but there he remains torn between his love for her and the shattered trust. Dan says in confession he will remember who drugged him and let him to die in his burning car dealership, and then...

Brooke has a end of the summer party on the beach; Nathan is home from basketball camp; Lucas deals with Brooke's rules for dating; Peyton deals with family issues; Haley tries to tell Nathan how she feels.

Lucas and Haley dig up, as each year, their previous predictions for the new school year; he decorated Brookes locker- they are arranged alphabetically, making the Scott brothers and Haley neighbors. Mouth pod-cast-interviews Ravens-star Nathan. Dan warns coach Durham he plans to have the school board remove him and Lucas he remembers his arson. Ellie tells Lucas the marijuana is for her cancer pain. When Haley asks coach for help with Nathan, he just gives her a detention slip for entering the boys locker room- Nathan is there to, but pays her no attention; next day, same place, they talk a bit. When dad Larry and Ellie wait for Peyton, she storms out blaming Lucas for 'trapping' her; left alone, dad makes her consider a shrink. Karen reminds Nathan how desperately he wanted Haley back. Dan tells the board the Ravens can be North Carolina state champions without Whitey, Karen praises his lessons on life for the boys- he stays on, but gives Mouth a scoop: he'll retire next year. When Dan nearly chokes Lucas, Peyton stops him and makes him tell he didn't start the fire but found Dan and dragged him out- Lucas now regrets that, Dan says a real man had left him and demands secrecy. Haley is happy to hear Nathan considers an annulment a lie, not when he proposes a divorce instead, hopeful again when he says the legal one year- waiting period gives them time to reconsider.

It's party time in Tree Hill. A masquerade ball at Tric provides the perfect opportunity for Haley to win back Nathan's heart, and for Brooke to seduce Lucas. Punk-pop sensation "Fall Out Boy" performs amidst the costume madness, while Peyton tries to come to terms with the new mother in her life. Meanwhile, Dan gives Deb an ultimatum, but soon finds she's a much more worthy opponent than he thought.

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.

Lucas struggles with the decision of whether he should play basketball in the wake of Keith's death while Brooke forces Rachel to deal with a dark secret. Nathan and Haley's wedding reprise is put to the test and Peyton decides to visit Pete in Chicago.