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.

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...

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.

Julie and Caleb walk down the aisle, as Ryan and Theresa face a difficult decision regarding their pregnancy. Marissa moves into Caleb and Julie's new castle on the cliff, and Seth struggles to find himself when things around him seem to fall apart. Life in The O.C. comes full circle from one year before.

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.

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.

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.

Ryan, and the World, are officially introduced to the bi-religious holiday Chrismukkah, thanks to Seth. And Seth insists he has TWO Godly forces helping him as he plays TWO girls. Marissa has some 'discount shopping' to do, and finds herself in an embarrassing situation, or two, or three. Kirsten does something that could cost her more than just her job. Summer and Anna each have very special gifts for Seth, but which one will he like the most? And a new boy enters the Newport scene.

Faced with the prospect of life in a group home, Ryan decides to run away from Newport, but Seth and Marissa convince him to stay and hide in a vacant building project. Jimmy discusses his recent financial woes with Kirsten, and she offers a solution. After Luke witnesses a close encounter between Marissa and Ryan, he confronts Ryan and a fight breaks loose. Ryan's presence in Newport is exposed in a big way, and two arrests are made.

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.

Seth and Kirsten want to avoid facing the world after their respective displays at Thanksgiving. Sandy has some advice for Jimmy, which doesn't sit well with Julie. Ryan and Luke find themselves getting along after an O.C. loved-one comes out of the closet to face negative reactions.

It's New Years and "love" is in the air. A sister returns home, and throws a party. Oliver casts his spell. Sandy and Kirsten find themselves in a rut, and out of their environment. Seth finally makes a decision between Summer and Anna. 2004 is born.

It's time for the annual Cotillion ball. Cherished by many, hated by most, it's the time when Newport's finest young ladies enter society. More information about Jimmy's business trouble comes to light, and Kirsten's loan to Jimmy is not happy news for Sandy.

Anna announces that she is leaving Newport to go back to Pittsburgh, which leaves Seth feeling saddened and guilt-ridden. Legal troubles brew for Caleb and Kirsten while Sandy works to solve them. Luke and Julie's secret romance is getting harder to contain, and Theresa brings a bit of trouble from Chino to the O.C.

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.

Sandy comes to Ryan's rescue once again, after he has a difficult stay in Juvenile Hall. Seth makes Kirsten aware of his anger over Ryan's situation, and Kirsten makes a compromise. Ryan's mother, Dawn, makes a surprise visit to Newport, and things don't go quite as she and Ryan may have planned. The monetary secret involving Julie, Jimmy, Kirsten and Sandy comes to a head.

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.

Changes are happening within the couplehoods of the O.C.'ers. Lines seem to be blurred. Oliver reveals himself as he falls apart, but not before Ryan is completely left in the cold. Someone loses school, one loses work, two lose their partners, and one more loses it all.

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.

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.

Kirsten's father, Caleb Nichol, comes for a visit along with his new girlfriend, Gabrielle. 24-year-old Grandma Nichol has arrived. Kirsten finds her job in jeopardy, while Sandy considers making a change. Much to Ryan's disappointment, Luke decides he wants a second chance with Marissa... but who will Marissa choose? Summer makes the moves on Seth, who wonders if her feelings are real.