Sandy tells Seth to say put, but Seth does whatever he can to be with Ryan and Taylor. Taylor hits a high at prom, while Summer falls flat with her surprising prom date. While playing shuffleboard, Seth and Ryan meet Mary-Suu, who helps Seth get center stage on the spring break television special. Alex invites Marissa to hang out with her friends. Julie comes clean to Kirsten about who Frank really is.
Taylor and Summer work together to try and find out what Seth is hiding, but Summer ends up getting hurt. The series includes elements of postmodernism, and functions as a mixture of melodrama and comedy. Meanwhile, Kaitlin realizes that she has feelings for Will. Lastly, Summer has to face leaving Newport without Seth and has a hard time saying her goodbyes. Parents and other family members also have storylines. Meanwhile, Marissa convinces Volchok to go to the prom and Ryan brings an unexpected old flame.
Sandy is able to fix the problems with Matt, but ends up neglecting Kirsten in the process. Meanwhile, Volchok escorts Marissa to prom, and Ryan brings an unexpected girl from the past. Meanwhile, at the Newport Group, Sandy works on a plan to save the company, and Charlotte convinces Julie and Kirsten to get back into the Newport social scene. The teens, as well as the adults, must figure out how to deal with each new situation that conflicts with Newport Beach's family ideals. Set in the upscale beach town of Newport Beach in Orange County, California, the drama focuses on wrong-side-of-the-tracks Ryan Atwood who is taken in by the affluent Cohen family. Kaitlin tries to stop her mother having a secret love affair.
Marissa has a hard time deciding and ends up going to Johnny's surf competition instead of filling out applications. Meanwhile, Marissa has to deal with being alone in Newport while Sandy deals with mounting business pressures. Julie also gets help from Kaitlin to help save the dating service. Marissa's nervousness around Ryan leads him to wonder if something has happened between her and Trey. After their new commitment from New Year's Eve, Seth and Summer begin making plans but fail to recognize their true feelings. When Ryan's dad comes to the Cohen's for dinner things don't go as planned. Summer starts protesting against poverty issues and turns the Cohens' Thanksgiving dinner into a homelesses' refuge.
At Brown, Summer and Che step up their activism and their actions lead to more freedom than they had imagined. At Harbor, Dean Hess makes a decision affecting Marissa's future while Summer faces off against Taylor Townsend when planning the Kick-Off Carnival. Alex's jealousy is fueled when Marissa enlists an unlikely partner to help her with the school bonfire. Elsewhere Che finally learns that Seth isn't his soulmate. At Brown, as Summer packs up to come back to Seth and the new Roberts family, she wonders if she'll be able to deal with Newport. Meanwhile, Matt, Sandy's new partner goes beyond what's expected and Julie manages to outdo Charlotte.
Ryan's mother arrives in Newport with a surprise for him. The teens must learn how to deal with adult problems as they leave adolescence behind. After graduation they all go out to eat and celebrate their graduation. Meanwhile, Sandy and Matt hit a bump in their pending hospital project; Julie and Kirsten come up with a matchmaking plan to get Julie together with Neil Roberts, but when it backfires, Julie has to hide from him. Their plan is a success, but it lands Seth and Summer in hot water with Taylor.
Meanwhile, Kirsten begins to relapse back into her old ways. Volchok is still mad at Marissa and Ryan, so he decides to crash Ryan's car. Ryan and Taylor have an accident while putting up the holiday lights and they end up in a sort of parallel universe, where all is not like it is meant to be, since Ryan does not exist. Meanwhile, Summer begins to question if Seth is the one for her after she and Seth get a psychic reading. Summer feels that Seth should find something in his life that he really cares about whereas Kirsten is having second thoughts about raising another child in Newport. Left to their own devices Ryan, Seth and Zach have a bonding session over video games and pizza but find it hard to stay away from their female counterparts. Despite her changes, Seth continues to support the new Summer.
Ryan and Seth spend much time navigating their relationships with girl-next-door Marissa Cooper, Seth's childhood crush Summer Roberts, and the fast-talking loner Taylor Townsend. Meanwhile, Sandy finds himself determining the future of the Newport Group and Julie finds herself in less than ideal surroundings. Zach, Summer and Seth drive to San Diego to pitch their comic book, and Seth is determined to use the trip to get Summer back. Also, Sandy and Matt land a deal for a new hospital, Kaitlin and Johnny start hanging out, and Julie continues to try to put her family back together. When Kaitlin finds out that Ryan and Taylor are working to get Julie and Frank together, she goes out of her way to make her mother like Bullit, forcing Julie to choose between Frank and Bullit.
Marissa is going to spend a year on a boat with her father as her graduation gift. Roberts, leading her to spend most of her Thanksgiving alone. Meanwhile, Julie and Jimmy are determined to protect Marissa, no matter the cost, and Kirsten continues to recover in rehab with Charlotte, who is hiding her ulterior motives. When one of the girls is elected prom queen, it truly becomes a night to remember. Ryan convinces Lindsay to take the paternity test.
Marissa captures the attention of the Coopers' sexy gardener, D. Meanwhile, the toll that Sandy's job is taking on him begins to strain the Cohen household. Taylor finally learns that the bonds between family are stronger than she thought. Taylor hits an all-time high in her life, while Summer hits bottom with her prom date. Sandy and Kristen Cohen, as well as Julie Cooper, have recurring storylines as the parents of the show's main characters.