Thanksgiving dinner at the Cohens descends into bedlam when unexpected guests arrive. Ryan returns to his hometown when his brother calls on him for a favor.

On Valentine's Day, everyone is preparing for the Valentine's singles benefit dance. Luke has a new crush: that being Marissa's mother Julie. Meanwhile, Sandy gives Seth some sex advice over his dating of Summer. Theresa Diaz, an old friend Ryan's, shows up in town as part of the catering services for the benefit, which forces Marissa to lay her feelings on the table that her breakup with Ryan may have been a mistake. Also, Seth and Summer take their friendship to another level.

The Ryan-Marissa thing is more iffy than ever when Theresa hangs in Newport. The telenovela-like suds-o-rama overflows with the Seth-Summer follies, the Luke-Julie fling and an insider who may be a threat to the Caleb-Kirsten biz.

Anna is leaving. Theresa is staying. Seth thinks he's the reason for Anna's planned return to Pittsburgh. And Ryan knows he's why Theresa is staying. But what is either guy going to do about it? Caleb is Riviera's Man of the Year (uh-oh).

Marissa runs away after learning a heartbreaking truth, to a place where only Ryan could find her. Sandy's mother visits for Passover.

Julie's wedding shower is anything but uneventful. Seth has lunch with Summer's dad.

The Cohen men, along with Ryan and Caleb set out to Las Vegas for a bachelor party. Meanwhile, the girls are having fun with their own adventures.

On Julie and Caleb's big day, Ryan may be leaving Newport forever. Everyone handles it differently.

It's been three months since Ryan left to live with the pregnant Theresa in Chino, and Seth subsequently sailed off to Portland to live with Luke and his divorced, gay father. With one week before school will start, Kirsten is furious that Sandy has yet to bring Seth back to Newport. Sandy says that they can't bring him back kicking and screaming, because that will only make him want to run away again. Also in the Cohen household, there's a group of re-modelers led by macho man Archie, creating a new family room and re-designed kitchen, a project that apparently was used to distract Kirsten from going from having two sons in the house, to none. Meanwhile, Summer tells Marissa that she's been hanging out with a new kid, but refuses to get close to him, saying she'll never get close to a boy again. Marissa knows just how she feels. She misses Ryan but just can't bring herself to call him to see how he's doing. Caleb's paranoia about being indicted is growing all summer long. Back at the Cohen household, Kirsten calls Seth in Portland and begs him to come home. Seth refuses, saying Newport is an awful place. Sandy decides to fly to Portland to possibly use reverse psychology to convince Seth to come home. He also visits Ryan in Chino to deliver him a plane ticket to Portland, thinking maybe the two could deliver an unbeatable one-two punch combination. It's apparent to everyone in Chino, including Theresa, that Ryan is miserable, and doesn't consider it to be his home anymore. Before heading up to Portland, Sandy speaks with Caleb in a parking garage, as Cal is paranoid his home, the office, and other places might be bugged and the phone lines tapped. Once in Portland, Sandy is shocked to see the level of hostility Seth shows his father. Seth seems content to stay in Portland, and continuing to resent his parents for letting Ryan go, and Ryan for leaving. Back in Newport, Jimmy and Marissa join Kirsten for dinner to keep her company, and Marissa goes into the pool house further fueling her missing Ryan. Sitting on the beach that night, she calls Ryan in Chino, but can't bring herself to say anything, so he lays there listening to her breathe, knowing it's her. Julie tells Marissa she's grounded because she's sick of being ignored. Marissa has a meltdown screaming, crying, and throwing lawn furniture into the pool unable to stand anymore of her evil mother or her evil stepfather. Summer visits the Cohen household with a box of Seth's stuff, telling Kirsten she's there to get rid of anything that ever reminded her of Seth. She dumps the box on the bed, and leaves. Later, just before Sandy leaves Portland he tells Seth that he's fine with him staying in Portland, as long as he knows he's safe and happy. As Sandy is leaving, Ryan is showing up, making his best attempt to convince Seth to go back. It doesn't seem to work until Theresa calls Ryan at Luke's house, and tells him she's lost the baby, saying the doctor couldn't find a heartbeat. Theresa's mother later reveals that Theresa was lying, and she never lost the baby. It's the next morning as Ryan is to leave that the two, Seth and Ryan, decide maybe going back to Newport would be the best thing for the both of them-and the two return to the Cohen household.

Seth and Zach squabble over who should take Summer to the prom and who will meet George Lucas for dinner over the publishing of the graphic novel. Meanwhile, Sandy takes drastic actions with a recovering Kirsten. Ryan starts to piece together what happened between Trey and Marissa, while at the same time, Ryan run into his old girlfriend Theresa. Also, Julie decides to murder Caleb to avoid going broke. But her attempts to poison Caleb take a surprise turn.

Ryan and Marissa arrive at Berkeley, and Summer and student/poseur Seth visit Brown for freshman orientation weekends. Familiar faces surface.

Harbor's Senior Prom brings out the best and the worst in everyone.

Sandy is voted Man of the Year. Kirsten hits the bottle. Summer tries to right an impulsive wrong. Ryan is blackmailed into stealing a car. Seth burns down his dad's office. Marissa gets Kaitlin out of trouble.

It's been three months since Ryan left to live with the pregnant Theresa in Chino, and Seth subsequently sailed off to Portland to live with Luke and his divorced, gay father. With one week before school will start, Kirsten is furious that Sandy has yet to bring Seth back to Newport. Sandy says that they can't bring him back kicking and screaming, because that will only make him want to run away again. Also in the Cohen household, there's a group of re-modelers led by macho man Archie, creating a new family room and re-designed kitchen, a project that apparently was used to distract Kirsten from going from having two sons in the house, to none. Meanwhile, Summer tells Marissa that she's been hanging out with a new kid, but refuses to get close to him, saying she'll never get close to a boy again. Marissa knows just how she feels. She misses Ryan but just can't bring herself to call him to see how he's doing. Caleb's paranoia about being indicted is growing all summer long. Back at the Cohen household, Kirsten calls Seth in Portland and begs him to come home. Seth refuses, saying Newport is an awful place. Sandy decides to fly to Portland to possibly use reverse psychology to convince Seth to come home. He also visits Ryan in Chino to deliver him a plane ticket to Portland, thinking maybe the two could deliver an unbeatable one-two punch combination. It's apparent to everyone in Chino, including Theresa, that Ryan is miserable, and doesn't consider it to be his home anymore. Before heading up to Portland, Sandy speaks with Caleb in a parking garage, as Cal is paranoid his home, the office, and other places might be bugged and the phone lines tapped. Once in Portland, Sandy is shocked to see the level of hostility Seth shows his father. Seth seems content to stay in Portland, and continuing to resent his parents for letting Ryan go, and Ryan for leaving. Back in Newport, Jimmy and Marissa join Kirsten for dinner to keep her company, and Marissa goes into the pool house further fueling her missing Ryan. Sitting on the beach that night, she calls Ryan in Chino, but can't bring herself to say anything, so he lays there listening to her breathe, knowing it's her. Julie tells Marissa she's grounded because she's sick of being ignored. Marissa has a meltdown screaming, crying, and throwing lawn furniture into the pool unable to stand anymore of her evil mother or her evil stepfather. Summer visits the Cohen household with a box of Seth's stuff, telling Kirsten she's there to get rid of anything that ever reminded her of Seth. She dumps the box on the bed, and leaves. Later, just before Sandy leaves Portland he tells Seth that he's fine with him staying in Portland, as long as he knows he's safe and happy. As Sandy is leaving, Ryan is showing up, making his best attempt to convince Seth to go back. It doesn't seem to work until Theresa calls Ryan at Luke's house, and tells him she's lost the baby, saying the doctor couldn't find a heartbeat. Theresa's mother later reveals that Theresa was lying, and she never lost the baby. It's the next morning as Ryan is to leave that the two, Seth and Ryan, decide maybe going back to Newport would be the best thing for the both of them-and the two return to the Cohen household.

Seth and Zach squabble over who should take Summer to the prom and who will meet George Lucas for dinner over the publishing of the graphic novel. Meanwhile, Sandy takes drastic actions with a recovering Kirsten. Ryan starts to piece together what happened between Trey and Marissa, while at the same time, Ryan run into his old girlfriend Theresa. Also, Julie decides to murder Caleb to avoid going broke. But her attempts to poison Caleb take a surprise turn.

Thanksgiving dinner at the Cohens descends into bedlam when unexpected guests arrive. Ryan returns to his hometown when his brother calls on him for a favor.

On Valentine's Day, everyone is preparing for the Valentine's singles benefit dance. Luke has a new crush: that being Marissa's mother Julie. Meanwhile, Sandy gives Seth some sex advice over his dating of Summer. Theresa Diaz, an old friend Ryan's, shows up in town as part of the catering services for the benefit, which forces Marissa to lay her feelings on the table that her breakup with Ryan may have been a mistake. Also, Seth and Summer take their friendship to another level.

The Ryan-Marissa thing is more iffy than ever when Theresa hangs in Newport. The telenovela-like suds-o-rama overflows with the Seth-Summer follies, the Luke-Julie fling and an insider who may be a threat to the Caleb-Kirsten biz.

Anna is leaving. Theresa is staying. Seth thinks he's the reason for Anna's planned return to Pittsburgh. And Ryan knows he's why Theresa is staying. But what is either guy going to do about it? Caleb is Riviera's Man of the Year (uh-oh).

Marissa runs away after learning a heartbreaking truth, to a place where only Ryan could find her. Sandy's mother visits for Passover.

Julie's wedding shower is anything but uneventful. Seth has lunch with Summer's dad.

The Cohen men, along with Ryan and Caleb set out to Las Vegas for a bachelor party. Meanwhile, the girls are having fun with their own adventures.

On Julie and Caleb's big day, Ryan may be leaving Newport forever. Everyone handles it differently.