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.

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.

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 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 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.

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.

Hailey discovers she isn't as welcome as she might have thought. Perhaps the Cohen house is full? Luke makes some new friends, while Seth and Anna try to tell a friend about their decision. Rooney sings, a lot, and Oliver noses, a lot. Trouble brews.

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.

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.

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.

Ryan and Marissa begin their life together as "friends", but both discover that it might be harder to do than to say. Theresa drops into Newport for work, and another visit. Julie and Luke realize the meaning of "booty calls", and Seth and Summer make a declaration.

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.

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.

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.