The Cohen family says goodbye in the series finale as the episode jumps six months after the earthquake to show the Cohens, Ryan, Taylor, Summer and the Cooper women trying to piece their lives back together. The Cohens find out that fixing up their old mansion would cost more than rebuilding it but Ryan and Seth see this as an opportunity to give Sandy and an expecting Kirsten a surprise that'll change their lives.

Kirsten hits rock bottom after Caleb's funeral, prompting Sandy to finally take action; Jimmy Cooper resurfaces and almost immediately renews ties with a mourning Julie; Jess bullies Trey into participating in a drug deal that turns into a shootout; Ryan finally learns the truth about what happened between Trey and Marissa, leading to a bloody confrontation.

It's a rainy day in Newport where Lindsay decides to take the DNA test and makes a difficult choice regarding her life with Caleb while Ryan helps her through it. Sandy still wants to help Rebecca with her case and tries to convince her not to run again. Kirsten is still upset and wishes her marriage would go back to normal and for Rebecca's case to be over with. Meanwhile, Seth thinks he's lost Summer forever untill Summer is unable to hide from her feelings once and for all. Marissa moves out of the Cooper-Nichol mansion and moves in with Alex after she tells her mother about Alex being her girlfriend.

Seth and Zach squabble over who should take Summer to the prom and who will meet George Lucas for dinner; Sandy takes drastic actions with a recovering Kirsten; Ryan starts to piece together what happened between Trey and Marissa, courtesy of Theresa; Julie's attempts to poison Caleb take a surprise turn.

It's Chrismukkah once again in The O.C. and this year, Seth wants to take it global. As Caleb is faced with the looming prospect of going to prison, Sandy convinces him to come forward and reveal the truth about his involvement with Renee. Julie and Jimmy spend some quality time together. Caleb's confession shocks the Cohen and Nichol family to the core, and nothing will be the same again.

Chrismukkah once again returns to the Cohens. 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. While - in the real world - everybody is worrying about them, except Taylor's mom, they eventually manage to fix things, also thanks to a letter from the past.

A new life for Ryan Atwood, the Cohens and the Cooper families, and basically everyone else in the wealthy, picturesque, secretive, turbulent community of Orange County. Be prepared to meet spoiled rich kids and watch Ryan struggle to fit in with his new crowd...

Seth works at a comic book store in Newport. Kirsten drops by the store to ask Seth if he has something to send Ryan in a "care package" she is preparing. Later, Seth tries to talk Ryan into coming to dinner at the Cohens' but the latter isn't easily persuaded, saying he works nights, etc. At her dorm, Summer and a friend named Che try to rally students for a protest. Summer gets a phone call from Taylor who seems to be in Paris.

In the immediate aftermath of a violent earthquake that rocks Newport, everyone struggles to stay together and keep their spirits up. Sandy and Kristen are stranded at the local shopping center where Kristen has an accident. Across town, Julie and Kaitlin are stranded in a demolished ice cream parlor on the pier with a pitiful worker of the place. Meanwhile, Ryan is seriously wounded with a piece of glass in his side, but keeps the news from Taylor to avoid panicking her. Seth soon learns of Ryan's condition and attempts to drive him to safety while Summer and Taylor search the ruins of the Roberts' house for Summer's missing rabbit, leading to Taylor having a confrontation with her mother.

Back to school for the O.C. kids. No one really wants to be there, except for the gossips. Ryan doesn't feel like he fits in at his new school, and Luke doesn't make the situation any better. Sandy accepts a case at his new job, a case that will test his relationship with Kirsten and her father. Anna and Seth hatch a plan. Marissa chooses her man.

It's Thanksgiving time in ‘the O.C.' It's time for family reunions, and Ryan gets called home by his family. Is it because of the holiday, or is it for a favor? Marissa decides to go along for the ride, but ends up going down Ryan's bad-memory lane instead. Seth plays the player role, but not very well.

It is graduation day for Ryan, Seth, Summer, and Marissa at Harbor High School. After graduation they all went out to eat and celebrate their graduation. Ryan's mother gave him a new car as a graduation present. Marissa is going to spend a year on a boat with her father as her graduation gift. Seth finally got into RISD for second semester. Summer is still going to Brown University in the fall. Volchok is still mad at Marissa and Ryan so he decided to crash Ryan's car.

The summer is coming to an end, and Seth hasn't returned home to Newport. In the midst of home renovations, Sandy and Kirsten are strained and missing their son. Ryan has begun his new life with Theresa in Chino, as Marissa is alone and in a dark place. Summer is slowly getting over Seth.

It's the annual "SnO.C." winter dance. Seth wants to take his relationship with Alex further, but she might have other plans. Marissa's secret relationship with D.J. is exposed, while Zach continues his pursuit of a Seth-free relationship with Summer. Sandy solves Caleb's legal puzzle ending with a shocking twist.

After Lindsay moves to Chicago with her mom, Ryan is heartbroken and Caleb's confused. Seth, Summer, and Marissa invite Ryan to the mall to get his mind off things. Caleb tags along to vent when Sandy tries to make amends with Kirsten by searching for her wedding ring or even a grand gesture that will take her back to when Sandy first proposed. Meanwhile, Alex learns that Marissa might not be as into her as she thought she would be. Kirsten and Julie call an editor for Newport Living but at the same time Julie's Riverside past catches up to her.

Sandy reluctantly serves as host/auctioneer at yet another OC benefit; Trey lies to Ryan to prove that he can be self-dependent; Carter reinvigorates Seth and Zach's comic book dream, much to the annoyance of Summer. Marissa moves in with the Cohens.

Kaitlin takes down the school mean girl by throwing a rager at her house. Sandy and Kirsten find time to bond with Ryan while Seth is away visiting Summer at Brown but all he finds is an empty dorm room. Meanwhile Julie continues work on the dating service and finds out a new surprise.

It's Valentine's Day in Newport, and everyone is preparing for the Valentine's singles benefit. Luke has a new crush, while Sandy gives Seth some sex advice. An old friend of Ryan's shows up in town, which forces Marissa to lay her feelings on the table. Seth and Summer take their relationship to another level.

After Caleb's confession, The Cohens try to welcome Lindsay as part of the family. Jimmy is faced with a choice when Marissa finds out about his relationship with his ex-wife, Julie. Seth attempts to be a "bad boy" like Ryan to impress Alex. Summer finds out what Zach did on his Christmas break while Ryan and Lindsay want to know if it is too awkward for them to be together.

Chrismukkah has returned to the Cohen house and Seth suggests to have a Bar Mitzvah to Ryan to raise money for Johnny's knee surgery after his accident but Ryan then pulls out after seeing Johnny and Marissa get too close.

When Taylor learns about Ryan's sleeping problems she devises a plan to help him but must then turn to Kaitlin when her plan backfires. At Brown Summer and Che step up their activism and it lands them more freedom than imagined. Julie also gets help from Kaitlin to help save the dating service.

It's Taylor's birthday and she hopes Ryan will tell her he loves her. She's unsure whether she should tell him she got into Berkeley as well. 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. Then the unexpected happens even though it's been predicted.

The Newport kids plan an end-of-summer trip down to Tijuana, Mexico (aka "T.J."). Jimmy has plans of his own, which don't sit well with Marissa. Sandy gets a new job, which Kirsten can't understand. Summer, Seth, Ryan and Marissa find themselves in a strange place together. Jimmy takes it too far. Disaster strikes one of the O.C. kids.

It's Bachelor and Bachelorette party time for Caleb and Julie. Caleb and the boys head off to Las Vegas while Kirsten organizes an evening at the Cohen house for Julie, strippers included. Seth and Ryan get themselves into a tricky situation in Vegas while back home, Summer pines over lost love, and Marissa comforts Theresa. Jimmy and Sandy learn of Caleb's true motives. Julie and Hailey take a swim, while Theresa has some shocking news for Ryan and Marissa.

It's a new era in Newport Beach. Kirsten and Julie try and work together at The Newport Group, while Sandy tries to find out what Caleb is hiding. Seth and Ryan go on a double date with Lindsay and Alex, but it ends differently than the four of them might have expected.