The O.C.

With the end of summer quickly approaching, tension fills the air in THE O.C. The Cohen family is desperate to convince Seth, who ran away at the beginning of the summer, to return home. Meanwhile in Chino, Ryan is working construction while a pregnant Theresa waits at home. Back in Newport Beach, while Summer is finding ways to deal with Seth's disappearance, Marissa is distancing herself from the world and masking her problems by reverting to old habits.

It's back to school for Seth and Ryan, who want to win back the attention they once had from Summer and Marissa. With opportunity beckoning, Hailey tells Jimmy about her plans to move in order to pursue her unfulfilled ambitions with fashion. Hoping to keep her near, Jimmy does something unimaginable. Meanwhile, Sandy explains to Julie that the district attorney is keeping a close watch on Caleb, and without representation, he might be in for a confrontation. Julie threatens Sandy to do something about Caleb's mess, or else.

Seth gets some help from Alex to prove that his friends don't know him as well as they think. Meanwhile, Summer gives some thought to how she really feels about Seth after she learns new information about Zach. Marissa is happy to share an evening with Ryan. But at school, Ryan finds himself embarrassed and frustrated after a run-in with new classmate Lindsay. Caleb's legal problems threaten to leave both Sandy and Kirsten unemployed as Julie makes sure she stays on top even if Caleb goes down.

As Seth and Sandy embark on new adventures, they take the rest of the family along for the ride. Ryan and Seth go on an awkward double date to see The Killers perform in concert, with unexpected results. Meanwhile, Julie finds herself overwhelmed by her new role at the Newport Group and, as usual, is forced to turn to Kirsten for help.

Winter finally comes to Newport, and Seth, Ryan, Summer and Marissa attend the annual "SnO.C. Winter Ball." Julie and Jimmy spend some quality time together as the chairs of the host committee and Sandy continues to close in on the truth Caleb has been hiding. Meanwhile, Julie discovers Marissa's secret when Marissa goes home at lunch to meet D.J.

The whole gang is invited to Chrismukkah at the Cohens, but Seth's favorite holiday is nearly ruined as secrets are revealed that will change the Cohen family forever. Summer and the gang make a plan to save Chrismukkah.

As one family strengthens, another will be changed forever. The Cohens, after Caleb's revelation, decide to try to accept Lindsay as a member of the family, while another family is heartbroken over the news that one of them is leaving Newport Beach. Meanwhile, Seth tries to be a "bad boy" like Ryan to improve his relationship with Alex.

After Caleb's reveal, Lindsay and Ryan grapple with their relationship: Is Lindsay Ryan's aunt or his girlfriend? Meanwhile, Summer meets Zach's family and it doesn't go so well. In the end it's an anniversary to remember as Sandy Cohen surprises Kirsten with a serenade at the Bait Shop. But Marissa ends up alone as D.J. leaves Newport Beach.

It's girls against boys when Marissa and Summer decide to plan a girls' night out and include Lindsay in the festivities. Ryan, Seth and Zach, left to their own devices, have their own bonding session over video games and pizza, but find it hard to stay away from their female counterparts. Julie and Kirsten collaborate on an idea to help the image of the Newport Group while Sandy and Caleb try to convince them there may be a better way.

Zach and Seth decide to start their own comic book based on their lives in Newport Beach. While browsing the sketches, Summer questions why she's been left out. Sandy decides to help an old friend find his daughter, but the search leads to even more questions. While Julie is away, Marissa's contempt for Caleb grows as she looks for new ways to rebel. Meanwhile, Ryan tries to help Lindsay satisfy her curiosity about Caleb.

Summer decides to take an active role in the making of the comic book, but Seth doesn't know if he can handle spending that much time alone with her. Sandy and Rebecca reminisce about days gone by as Kirsten tries to convince Caleb that he could have a relationship with Lindsay. As Caleb decides what kind of future he wants to have with his daughters, Alex asks Marissa where their friendship is going.

Sandy tries to make up for keeping Rebecca's return a secret from Kirsten by showering her with Valentine's Day gifts. Zach, Summer and Seth head to San Diego to pitch their comic book idea, and Seth is determined to use the trip to get Summer back. Julie returns from her European vacation and has decided to reconnect with Marissa. Meanwhile, Ryan wants to spend Valentine's Day with Lindsay, but her loyalty to Caleb gets in the way.

While Rebecca pays her last respects to her father, Kirsten grows impatient with Sandy's long absences from home and pays Rebecca a visit. Alex invites Marissa to hang out with her friends. Meanwhile, Caleb decides to remove all doubt that Lindsay is his daughter.

It's raining in Newport. Marissa tells Julie that she and Alex are an item and decides she has to get out of Caleb's house. Summer is faced with a big decision as she prepares to go Italy with Zach. Ryan convinces Lindsay to take the paternity test and everyone anxiously awaits the results. Meanwhile, Sandy finds himself stranded in a motel room with nothing but a few snacks, champagne and Rebecca.

Lindsay's actions have left Ryan and Caleb confused. Marissa is trying hard to make her new living situation work, but she needs a break and agrees to join Summer, Seth and Ryan at the mall. Julie and Kirsten await the arrival of Carter, the new editor of Newport Living, but Julie is distracted when she's visited by Lance, an opportunistic man from her past. Meanwhile, Sandy and Caleb finally bond over all of their recent experiences.

Seth is determined to bring back the spirit and fun times of last year and won't stop until his plan is fulfilled. Alex's jealousy is fueled when Marissa enlists an unlikely partner to help her with the school bonfire. Meanwhile, Kirsten wants Carter to stick with the magazine despite his reservations and Sandy helps Julie keep her blackmailer at bay.

When Ryan's past comes for a visit, he is worried that nothing good can come of it. Meanwhile, the Cohen family has welcomed the visitor from Chino with open arms. Marissa and Ryan continue to explore their newfound friendship, while Seth and Summer face some unforeseen news. Meanwhile, Julie admits her mistake to Kirsten and looks to Caleb for help.

When Sandy becomes the honorary chair of the Newport Beach charity yard sale, he solicits help from Trey, who has his first run-in with the Newpsies. While Sandy auctions off Newport's finest, Kirsten and Carter share a table. When one of the auction's most expensive pieces goes missing, it's Ryan and Seth who also could use some help. Meanwhile, Trey looks for a more permanent place to live as the Cohens welcome yet another houseguest.

It's Trey's birthday and Marissa, anxious to help Trey and Ryan forge a relationship, throws a birthday party for Trey at Caleb's mansion that turns out to be a rager. Sandy and Carter hit the waves together and decide to double-date and Summer discovers Reed's true identity, leaving Seth in hot water. Meanwhile, Julie leaves town on the heels of her disgrace, but comes home and reminisces about the Whitesnake concert with an "old" friend.

After the rager at Caleb's mansion, Sandy and the boys devise a plan to save another Atwood from jail time. Kirsten and Carter, fulfilling more than their editorial duties, take a trip to the wine country. Meanwhile, Caleb returns from Europe and is ice-cold to Julie's hot advances.

Sandy, Seth and Ryan travel to South Beach to visit the Nana, who is living in Miami Beach, FL. While playing shuffleboard at the Nana's coastal-living retirement community, Seth and Ryan meet Mary-Sue, who helps Seth get center stage on "Music Video Nation's" Spring Break 2005 television show hosted by Swerve and Pixie, star of "Sherman Oaks: The Real Valley." T.I. performs his hit single "Bring Em Out" in the episode. Meanwhile, on the Pacific Coast, Carter packs his bags and leaves Kirsten alone at "Newport Living" and Trey misinterprets Marissa's friendship.

Since Carter's been gone, Kirsten has been drinking more than just tomato juice for breakfast and when Sandy questions her, he's left alone in the bedroom. When Marissa acts nervous around Ryan, Ryan wonders if something has happened between Marissa and Trey. Summer, tired of Seth and Zach acting foolish, confronts Reed about the graphic novel and finds herself center stage at the "Atomic County" launch party. Meanwhile, Caleb shows Julie that a picture is worth a thousand words.

Sandy and Caleb confront Kirsten about her behavior. Ryan, looking for the truth about Trey and Marissa, heads home to Chino. Meanwhile, Summer won't let her three-way relationship with Zach and Seth get in the way of her attending the prom. And, Julie and Caleb toast to their final evening together as husband and wife.

Sandy must make a life-changing decision to save his and Kirsten's marriage. Seth, Summer, Marissa and Ryan are caught in the crossfire at The Bait Shop and Jimmy Cooper, worried about Marissa and his family, rushes home to Newport Beach.