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.

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.

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.

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.

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...

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.

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 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 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 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 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'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.

When Sandy forgets his and Kirsten's 20th wedding anniversary, he finds himself going to a lot of trouble to make it up to her. Seth and Ryan's respective relationships with Alex and Lindsay add to the trouble, and doubt falls upon their futures together. Marissa and Julie continue to butt heads over DJ, and Summer wants to take her relationship with Zach to the next level.

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.

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.

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.

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.

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.

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.

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.

Couples are plentiful in 'The O.C.' It is a night of firsts. Now that they are free to love one another, Ryan and Marissa plan their first official date. Kirsten sees her father with a new woman, and fears Sandy has found a new woman of his own. Seth takes matters into his own hands with a girl, and is taken by another girl.

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.

Everyone is back home in Newport, and Marissa is recovering. Julie points her finger at Ryan and forbids him from seeing Marissa, who does not appreciate the help. Sandy starts his new job, but finds himself surprised by the case work. Kirsten finds herself surprised by Sandy's new co-worker. Ryan enrolls at his new school, with conditions. Julie gets an intervention, and Jimmy gets a new roommate.

Now that Ryan and Seth have returned to Newport, its time to get back to school. The boys reunite with their former girlfriends but it becomes apparent that things will not be going back to the way they were. Caleb's legal troubles catch up with him, and Hailey has bad news for Jimmy.

It's Thanksgiving time. Volchok is back in town and Ryan seems eager to take revenge. At first Sandy and Kirsten try to talk him out of this but, then, Sandy makes Ryan face Volchok. Julie's behavior turns Kaitlin away and permanently jeopardizes her relationship with Dr. Roberts. Summer starts protesting against poverty issues and turns the Cohens' Thanksgiving dinner into a homelesses' refuge. It's clear she hasn't got over Marissa's death yet. Veronica kicks Taylor out as soon as she discovers her beloved daughter married a French man during her European trip.

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 Trey's 21st birthday and Marissa, anxious to help Trey and Ryan forge a relationship, throws a birthday party for Trey at the Cooper-Nichol mansion that turns out to be a rager. Seth is left in hot water by both Summer and Zach, but why? Sandy wants to continue his friendship with Carter, leaving a confused Kirsten. Meanwhile, Julie shares some memories with an "old" friend and in the process learns a few things and gains a few ideas.

Taylor's ex-husband comes to Newport and causes a rift in her relationship with Ryan. Seth goes to Seattle to obtain Dr. Roberts blessing, while Summer "travels to the past" for 48 hours. Kaitlin finds love, while Julie finds problems with Kirsten.

When Ryan and Sadie go on a road trip to search for one of Johnny's relatives they end up in Ryan's old neighborhood in Chino, which brings the two closer together. While the two are away Marissa is implicated in Johnny's death and Seth and Summer learn the truth about Julie and Dr. Roberts new secret.

Ryan overcomes his indecision and competes with Henri-Michel for Taylor's affections. Che leads Seth on a trek of spiritual renewal. Meanwhile, Kirsten and Julie have to do some damage control.

Marissa plots to ruin her mother's happiness by inviting someone from her mother's past to the wedding shower, while Sandy attempts to hide Theresa's return to the O.C. from Ryan. When Ryan discovers Sandy's lies and Theresa's reasons for coming back, he puts himself in a dangerous situation. In the meantime, Seth's unimpressive first meeting with Summer's father leaves their relationship in doubt.

Ryan decides to go and invite his mother to his graduation party. Taylor and Summer work together to try and find out what Seth is hiding, but Summer ends up getting hurt. Marissa realises she is in bad company after she finds out how low Volchok's friends can go. Sandy is able to fix his work problems with Matt but while doing so he hurts Kirsten.

Sandy, Ryan and Seth prepare for Kirsten's upcoming 40th birthday party, however Kirsten learns some news that will change her life forever. Kaitlin tries to stop her mother having a secret love affair. Taylor visits a therapist and Ryan pretends that he doesnt miss her. Elsewhere Che finally learns that Seth isn't his soulmate.

Oliver plans a trip for the gang, but things don't go as well as everyone might have hoped- except for Oliver of course. Summer really plants herself into "friendship" within Anna and Seth's relationship. Jimmy and Sandy decide to go into business together. Caleb and Julie return from Europe, and Hailey and Kirsten butt heads. Ryan finds himself in the cold.

When an old friend returns to Newport, Ryan decides to help her, which causes problems for him and Sadie. When Summer and Seth run into another rough patch Taylor tries to help them out. Sandy has to deal with more problems with the Newport Group and Marissa must deal with being alone.

Kaitlin prepares herself to head back to school. Ryan has doubts about his relationship with Marissa after helping out Sadie. Kirsten and Julie make plans for a Valentine's Day party.

Sandy and Matt's hospital project hits a roadblock. Kirsten and Julie run into troubles of their own with their matchmaking business. Marissa confesses her feelings to Johnny. Summer finds out out about Seth.

Spring has flung in Newport where Marissa recruits Ryan to help her with Harbor School's Pep Rally Bonfire. Alex accepts that her and Marissa are from two different lives and knows she is fighting a lost cause. Seth is stuck and misses last year's good times while Summer disagrees and tells him it's time to move on. Meanwhile, Julie still doesn't know what she is gonna do about her blackmailer and seeks some advice from Sandy. Kirsten wants Carter to stick with the magazine despite his reservations.

Sandy, Seth and Ryan travel to Miami to visit the Nana after she tells Sandy she is getting married. Unable to go because of work, Kirsten is left on her own to deal with her feelings for Carter. Trey misinterprets Marissa's friendship; Zach invites Summer to a home-cooked dinner.

Sandy and Jimmy have plans to sign papers for the Lighthouse... but is Jimmy ready? Oliver makes his plans official to Ryan, but Ryan just cannot catch a break from anyone and finds himself in an all too familiar position. Summer has a "big" new boyfriend... for a little while. And Julie gets a job.

Graduation is just weeks away and Ryan, Seth, Summer and Marissa leave Newport to attend their respective pre-frosh orientations at UC Berkeley and Brown. While dropping the boys off at the airport, Kirsten is surprised to see Theresa and her all-too-familiar-looking baby boy. While visiting Brown, Seth runs into Anna on the quad and they instantly connect. Could this be the end of Summer and Seth? Meanwhile, Kirsten and Sandy attend a hospital benefit where Kirsten vents her frustrations and falls back into an old habit.

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.

Kaitlin starts going out with Johnny with the sole motive of making Marissa jealous. Seth starts getting nostalgic as he prepares for his Brown interview.

Ryan thinks about not inviting Marissa to his 18th birthday after their falling out but Sandy tries to get him to invite a relative. After months of avoiding telling Summer and Marissa the truth Neil and Julie tell Summer and Marissa the truth.

When college acceptance and rejection letters are received the kids must consider what path they are going to follow. Ryan and Sadie are trying to decide what they will do after high school. Taylor holds a college party and Summer and Marissa fix their friendship problems.

Social Chair Marissa tries to plan this year’s carnival but is having much difficulty due to a little pest named Taylor. Sandy is surprised to find Kirsten has been released from rehab but instead of informing him, she has been living with another woman named Charlotte who she met in rehab. Julie and Sandy meet with the Dean and Dr. Kim to discuss Ryan and Marissa’s future at Harbor High. Later Ryan and Marissa partake in a similar meeting. Elsewhere Jimmy meets a man and feels more than open to discuss his money problems with him.

Julie and Dr. Roberts announce their engagement and the Cooper ladies move in with Summer and her dad. Meanwhile, Marissa drifts away from the group and Summer when she seeks solace in the bad company of Volchok and his crew. Ryan tries to move on with Sadie, but Seth's concerns for Marissa get in the way. At the Newport Group, Sandy's woes with Matt continue and Kirsten surprises Seth with a night out.

When Seth visits Summer, she realizes that her materialistic, gossiping self may be forever gone ever since she went to Brown. Ryan helps Taylor with her divorce. Temptation stirs when Kaitlin and Julie vow to stay out of trouble. And Sandy longs for a guy's night out.

Marissa struggles with attending a public high school, and her new friends make Ryan jealous; Charlotte's ruse is up when she learns that Kirsten did not inherit any money from Caleb; Julie's mansion is repossessed, leaving her with nothing; Taylor's power play dethrones Summer as commitee chairman, who then learns an interesting secret about her and Dean Hess.

Ryan and Seth go to Mexico to find Volchok, but Seth secretly phones home worried about what Ryan might do if they find him. A distraught Sandy and Kirsten decide to go after the boys and try to stop Ryan before he does something he might regret. Meanwhile, Julie and Kaitlin are forced to participate in a clothing drive at the school, and Summer and her hippie friends try to save a tree.

When the gang heads to The Bait Shop to see The Subways, Taylor's horsing around causes a major rift between Seth and Summer. Marissa, determined to end the potentially explosive rift between Ryan and Volchok, does whatever it takes to watch out for Ryan. Meanwhile, Matt, Sandy's Newport Group partner, goes above and beyond the call of duty when he learns he has to cut Newport Group staff.

Marissa visits Johnny at his house after his accident to see how he is doing. Julie and Kirsten get a contract for their new catering business while Sandy, Ryan and Matt meet with investors.

It's winter break and Kaitlin Cooper has returned home from her Montecito boarding school.

Harbor School's Senior Prom brings out the best and the worst in everyone. Taylor hits a high at prom, while Summer falls flat with her surprising prom date. Seth and Anna come up with a prom plan to win Summer back. Meanwhile, Marissa convinces Volchok to go to the prom and Ryan brings an unexpected old flame. When one of the girls is elected prom queen, it truly becomes a night to remember. Later, when Taylor's prom funds are missing, Ryan returns to his old ways and prom night turns brutal.

Kaitlin is assigned a tutor after she presented a ruffled report to her class. Julie comes clean to Kirsten about who Frank really is. Summer and Seth continue their recent commitment despite how they really feel about it. When Ryan's dad comes to the Cohen's for dinner things don't go as planned.