It's four years into the future and the Tree Hill gang has finished college. Now, their lives have taken completely different directions. Lucas has written and published a book, Brooke has made it big in the fashion industry with her brand "Clothes Over Bro's", Peyton is pursuing a career in the music business, and Nathan and Haley continue to raise a now older James.
Haley tries to make Nathan understand what is going to happen if he doesn't change his ways. Lucas and Skills prepare James to compete in a race-car competition. Meanwhile, Brooke faces problems at her company and Peyton meets Lucas' new girlfriend. Mouth gets a job but it doesn't turn out well.
Now that Peyton and Brooke are back in Tree Hill, Lindsey worries that the two might threaten her and Lucas' relationship. Meanwhile, Nathan visits Dan in prison (his first visit in four years) and gives him a picture of his grandson. Meanwhile, Haley tries to persuade Quentin to return to school, Brooke opens her store in the old Karen's Cafe and Peyton signs her first band.
Peyton wants Haley to work with Jason on his music but he refuses to. Mouth is involved in a relationship with his boss and age is a factor in it. As the opening of Clothes over Bros approaches, Brooke finds herself in a few problems. Nathan takes strides to help Quentin.
In this flashback episode, memories are looked back upon. Lucas surprises Peyton in Los Angeles and they talk. He asks her something and is left with a surprising answer. Meanwhile, Nathan's temper triggers up after a guy reminds him of his cheating in high school basketball games.
It's confrontation time in Tree Hill, as Lucas confronts Peyton about her nasty behavior towards Lindsey and Brooke must confront Victoria about meddling with Peyton's record label. Meanwhile, Nathan begins to grow closer to Carrie, Haley continues to struggle in dealing with Quentin, and Mouth must choose sides between his co-workers and Alice.
The Honorary Title performs at Tric and Mia plays her song there as well. Carrie tries to get closer to Nathan. Brooke sets Mouth up on a blind date with her assistant and Lindsey confronts Lucas about Peyton.
Brooke continues to pursue Owen. Haley sees something happening in Peyton's office. Quentin needs to change his negative approach in order to succeed in the season-opening game. Mouth tries to win Millicent back.
Haley, Brooke, Peyton, Lindsey and Mia get locked in the Tree Hill High library on the night of the Ravens' first game. Also Brooke tries to stand up for her mother, while Lucas and Nathan discuss whether to tell their loved ones about their indiscretions.
Brooke runs into someone from her past while on a trip to New York with the Tric bartender, Owen. Nathan and Lucas attend Dan's hearing while they try to protect Jamie from him. Mia gets an offer from a major record label and in the meantime, Haley and Nathan's marriage is on the rocks.
On the eve of Lucas and Lindsey's wedding, they conspire to save Nathan and Haley's marriage. Brooke pairs Peyton with an old boyfriend, while Rachel and Dan return to Tree Hill.
On Lucas and Lindsey's wedding day, Peyton must choose between intervening and losing Lucas forever. Nathan uses the event to try to mend his marriage to Haley. All are shocked when Dan, who is out of prison on parole, shows up at the event.
Lucas picks up the pieces after being left at the altar by Lindsey, while Nathan and Haley deal with the repercussions of Jamie's abduction. Dan is free for now, but he must find himself a job to convince the parole that he is changed for good. Brooke is haunted by her past as a woman from adopting asks her questions, while Peyton gets a visit from an old friend.
Nathan and Haley have learned from the mistakes with the nanny, so they decide to interview potential nannies or mannies, but it goes in a completely different way. Meanwhile Brooke still wants to go ahead with adopting a baby. Mouth and Millicent take a new step in their relationship and Quentin must reconsider his intentions.
Nathan and Haley throw a birthday party for Jamie. Deb hired a clown, and Haley is not happy with it since it's a creepy one. Lindsey returns to Tree Hill for Jamie's birthday, which gives Lucas hope that the relationship will be rekindled. When Dan arrives, Deb's mood swings fast and in the meantime Brooke and Peyton attend the party with baby Angie.
Lucas investigates Dan's heart condition. Haley struggles with letting Dan into Jamie's life. Peyton also still struggles with her guilt over Lucas' breakup and Mouth finally gets the chance to be a sports anchor.
Lucas is crushed by devastating news. Quentin is pushed to his limits during a Ravens game. Dan's is second on the donor recipient list to get a new heart. Haley thinks about her decision to release a new album while Brooke's baby undergoes emergency surgery and a shocking truth stuns Peyton, told by Lucas.
The Tree Hill residents are forced to face their fears as Dan turns over on a new leaf and Brooke taking the hardest decision of her life. In the meantime, Haley's career takes a turn and Peyton is visited by somebody from her past. Mouth and Millicent meet a new face. With all, Lucas and Brooke help each other through the struggles.
