Brooke buys Karens Cafe, and turns it into a Clothes Over Bro's boutique. Everyone goes to the opening of the store, including Brooke's Manager mother, who has seemed to track her down. Lucas and Peyton cause friction at the opening.

Nurse Carrie isn't just an ideal playmate for Jamie, who has nightmares since Skillz told him too much about Dan. Her charms should make Haley jealous, but she doesn't realize yet that Carrie really lusts for the hunky husband. Mouth is deputized by the night-shift to ask for better working conditions from their boss Alice; he actually may earn a TV reporter spot as her "play thing". Peyton clashes instantly with Brooke's bossy mother, Victoria, who scares her new label's only star, Mia, and calls Brooke too dumb to run the fashion business herself. Lucas considers proposing to Lindsay and won't accept Peyton's claim that he 'gave up on their true love' during or after his 'ambush proposal'.

It's a Tree Hill reunion as the entire gang gathers at Tric to see musical group The Honorary Title perform. Victoria turns up at the club which infuriates Brooke. Meanwhile, Brooke sets up her assistant Millicent with Mouth but Alice ruins the set-up for him by threatening to have him fired if he kisses Millicent. Peyton arranges for Mia to sing at Tric and Lucas proposes to Lindsay which stuns Peyton.

Lucas proposes to Lindsey and Peyton is the first one to know the news. Haley is upset at Lucas and Peyton for witnessing their kiss before he proposed to Lindsey. Next day Lindsey shows her ring to Haley and Brooke. Mouth finds out that Alice has been fired for sleeping with an unnamed employee and continues to pursue Millicent and finally wins her over when they watch a televised ballet recital. Carrie continues in the pursuit of Nathan and Brooke is intrigued by Owen and wants to get to know him better but cannot understand why he doesn't respond to the instant Brooke charm.

Lucas confronts Dan's announcement about his life expectancy of only 6 months without a heart transplant. He calls Dan a liar until the cardiologist confirms it. Nathan wrestles with his feelings, and Jamie's burning desire to get acquainted with his 'cool' grandfather, while Dan begs for a last chance to repair his shattered family. Nathan and Jamie come up with a daring alternative for the injured Ravens. Mouth suddenly gets a triple break as sports presenter.

Brooke has to deal with giving up her baby Angie. Haley's career takes a turn for the better and Peyton is visited by somebody from her past. Meanwhile, Dan awaits a new heart as Lucas makes a decision on who he wants to be with. Elsewhere Mouth makes the decision to move to Omaha when Millicent agrees to go with him.

Nathan and Haley must parent Jamie in the face of a school bully, while Lucas and Peyton adjust to life as a live-in couple. Brooke finds being a role model not as easy as she expected, and Marvin gets his old job back. Marvin is surprised to find out that his new intern is someone from his past.

As Lucas takes a trip to Hollywood to meet his film director, Nathan gets a pro basketball try-out. Peyton struggles with Mia to focus on her follow-up album, while Millicent confronts Marvin about Gigi. Julian approaches a dubious Brooke about designing clothes for his movie, and Haley takes a reluctant Jamie to his school talent show.

Nathan gets some news about his future on the Chiefs. Peyton gives birth to hers and Lucas' baby daughter, Sawyer, and receive a surprise visit from Karen. Dan is on death's door, while Brooke and Victoria prepare to re-launch Clothes Over Bros.

A disgruntled Renee makes her pregnancy known in the national media. Quinn tells David that she wants a divorce and spends the night with Clay. Mouth quits his job at the station after he is forced to report on the scandal surrounding Nathan. Brooke's fashion show is a huge success but Victoria warns her about Alex and Alex's obvious designs on Julian.

Julian gives Alex another chance and they continue to work on her script which he believes is very good but Brooke is not happy. Brooke reconnects with Chase to make Julian jealous and it works. Mouth gets to tell the truth on air about the allegations against Nathan much to his station manager's horror. Milicent begins to take weight loss tablets after Alex tells her she is a plus-size model. Elsewhere, Haley offers to pay off Renee unknown to her that Rachel and Dan have got to her first.

Clay finally gets some hand muscle control back. As he predicted, Nathan had no reason to be gloomy about his first contract, football talent Troy, which is signed to all parties' satisfaction. Julian and Brooke stand up to his mother, who has to back down on the fancy wedding plans but relapses into drinking. After some occupational therapy for Mouth and himself, Chase handles his Alex-Mia-dilemma. In Nathan's absence, Jamie finds it even harder to face the peril of peer ridicule for getting braces, which Haley only compounds by wearing a 'commiserative' eye-patch.

As Haley's due date approaches, she takes steps to ensure that all her friends and family will be ready when the time comes. Brooke and Julian also prepare to begin a family, while Chuck turns to Chase for help with a problem.

Nathan, Jamie, Clay, Julian, Chase and Chuck have a camp-out on the Rivercourt. Meanwhile, Brooke, Quinn, Alex and Lauren take a trip to Puerto Rico.

Haley and Brooke get ready to re-open Karen's Café as Brooke's pregnancy progresses. At her scan she discovers that she is expecting twins. Nathan and Clay set off on the road to scout new talent and it forces Nathan to finally go and see Dan. Chase leaves for the Air Force leaving behind two disappointed people - Chuck and Alex. Meanwhile, Mouth and Millie start their new morning show together but Millie is wooed away to start a new show with another co-anchor in Charlotte.

Chase confides only in Chuck his plan to move Alex's things into his place. They ignore Chris Keller made her an offer for a career-boosting, national tour. As even the psychiatrist Clayton grudgingly consults can't properly diagnose his problems, Nathan decides with support from Jamie and Haley to attend in his pace the European forum for international sports talent scouting. This allows Dan to prolong his stay and carry out a mysterious plan. Julian warns Brooke that Victoria tries trough him to sabotage her father's apparently business-wise sound project to co-found a male fashion label.

Chase is heartbroken after Alex's desertion to take the tour Chris Keller advised, yet overcomes his bitterness toward Keller, who pleads her artist temperament was a lost case from the start. Julian is near despair about the unused studio until a TV series project comes within reach. Alas coaxing the studio proves tragically incompatible with paternal duties, while Brooke charms investors for her boys fashion project with her father. Clayton's problem is worse then thought, as Quinn discovers spying on him. Haley now runs Karen's café, but her cook is sick, so Dan steps in but that costs some bigot customers, and a mystery competitor opens across the street.

Dan enlists Julian to help in his search for Nathan. Mouth fills Clay in about Nathan, as Haley explains Nathan's disappearance to Jamie. Brooke gets an idea of how to bring patrons to an empty Karen's Café, and Chris Keller confronts Chase about Tara.

Julian finally sells his One Tree Hill series concept to a studio and is hired to complete the script. Clayton and Quinn, who welcomes Sara's memory to, patiently win Logan's trust to become a warm; close family. Chase gets over his confidence crisis as bar manager just before he's offered a chance to buy Tric from Karen on the boat burning day. After Julian scolds father-in-law a useless father and Brooke 'surprises' her divorced parents back in bed, an unexpected business move makes up for a lot.