A troubled teen boy's life is forever changed when, upon landing in jail for a crime his brother committed, a public defender from Orange County, California decides to take him into his home.

Ryan decides to run away from Newport before he can be put into foster care. Seth and Marissa help him find a place to stay without being found.

Ryan's mother arrives in Newport.

It's the annual Cotillon Ball. Ryan continues to pursue Marissa, Seth makes friends with a newcomer, and Jimmy finds himself in hot water.

Ryan takes a job at the Crab Shack diner where a co-worker, named Donnie, might mean bad news for the Newport kids when he takes Ryan and Seth out to party queen Holly Fischer's parties where drugs and alcohol flow freely. Ryan asks Marissa out on a date, and when Luke again tries to intervene, Donnie decides to take matters in his own hands when he tries to starve off Luke... with a gun. Meanwhile, Sandy attempts to help Jimmy sort out his life, and gives him some bad news that be may go to jail for his unauthorized loans to cover his tracks. Also, Julie reveals a long-held secret to Kirsten about her past.

On his birthday, Kirsten's father pays a visit to Newport with his 24-year-old girlfriend, but things get messy when the girlfriend makes advances towards Ryan.

Ryan, Seth, Marissa, and Summer plan a trip to Tijuana. The trip descends into chaos when secrets are revealed and lives are put on the line.

It can't stay in Mexico. Not after heartbroken Marissa took all those pills. And not with Marissa's mom trying to have her institutionalized - something Ryan, Seth, Summer and Marissa don't want to happen.

Calculus. AP English. History. The ways of the human heart. Not everything learned at Harbor High is on the schedule of classes. The Cohen casa is a house divided when Sandy takes an environmental case against Kirsten's father.

Work keeps Sandy and Kirsten apart, Rachel makes a play for Sandy, Julie's secret lover is revealed and - omigod! - Summer realizes she likes Seth (but don't ever tell anyone).

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.

No one was supposed to see what happened. But Luke did. And so did Ryan. Now, somehow, all Newport knows that Luke's dad has been living a lie. And subsequent gossip raises questions of secrecy and trust.

Ryan is introduced to a Cohen family tradition as unpleasant memories of the holidays back home resurface. Marissa sinks deeper into depression.

It's New Year's Eve. Ryan may have competition for Marissa's affections. Kirsten's sister stirs up trouble.

Ryan doesn't know much about Oliver, Marissa's therapy friend, but he knows he doesn't like him. Yet, Ryan still assists Oliver when he runs into trouble with the law at a Rooney concert.

He says he's a friend. But who can believe a word Oliver says? During a group getaway in Palm Springs, Ryan is sure he's wise to Oliver's game. Marissa is just as sure Oliver is a friend who needs help.

People who won't be on each other's Christmas-card list: Ryan and Oliver. Their rivalry for Marissa intensifies, with Ryan risking his standing at Harbor to unmask Oliver's true character.

Now sure of the truth, Ryan races against time to keep Oliver from hurting himself or Marissa.

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).

Operation Protect Marissa! Seth and Ryan plan to keep Marissa from finding out about her mom's affair. It also becomes Operation Rescue Hailey when they inadvertently attend a Hollywood party where she's a stripper.

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

Engagement announcements are joyful news, right? Not when it means the one person Kirsten despises will become her stepmom. And not when Marissa will have a new family arrangement she doesn't want.

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.

The boys are back. Every status is quo. Except: Summer won't kiss and make up. Ryan catches Marissa in a clinch, the DA busts Caleb, Hailey bails and the re-modelers are like a wrecking crew. Home sweet chaos.

Seth pulls off a magnanimous gesture for Summer, then blows it. Lindsay and Ryan become Physics lab partners and share some romantic chemistry. Embattled Caleb names Julie as Newport Group's CE-uh-O.

It's not a date, it's a group hang. So Seth goes with Lindsay, but looks for Summer. Ryan goes with Alex, but would rather be with Lindsay. And Alex...well, stay tuned. That new CEO has a style all her own.

The winter dance is near and a Ryan-Lindsay hook-up is off, on, off, on, off like a light switch. But all will be smoothed over by the time of the big Newport social event. Or not. Plus: Caleb's secret revealed.

Friends, festivities, eight days of gifts, another day with a whole lot of gifts. Seth's formula for the perfect Chrismukkah may come undone when Caleb's confession rocks the Cohen world.

Time to move on: Jimmy decides to relocate to Maui. Time to make a move: Ryan and Lindsay wonder about a first kiss. Time to bust a move: Seth turns bad boy in an attempt to impress Alex.

Sandy didn't forget his 20th anniversary. Honest. Just ask him. And just watch him squirm as he tries to make things right. Also, Seth and Ryan are grounded; DJ calls it quits with Marissa.

The ABC's of love. When Alex wants to spend time with her ex, Seth says "X" must make room for "I" and "U." But there's something Seth doesn't know. Julie has a makeover idea for the Newport Group.

Hostilties heat up between Sandy and Kirsten when Sandy decides to help Max Bloom, his mentor in law school, find his daughter, Rebecca, whom was Sandy's first love. Meanwhile, Seth and Zach start up a comic book based on their lives in Newport, while Summer questions why she's been left out. Ryan makes the attempt to unite Lindsay and Caleb after Lindsay tells Ryan she is curious in getting to know her "new" father. While Julie is in Paris, Marissa looks for new ways to rebel and in doing so, her friendship with Alex increases during a trip to Los Angeles to get some of Alex's things from her former girlfriend.

After hearing about Lindsay and Ryan's failed attempt at dinner with Caleb the night before, Kirsten arranges a dinner that she can supervise. But her presence makes no difference when the hot-tempered Ryan and the egotistical Caleb immediately butt heads and disaster strikes when Caleb collapses from a sudden heart attack. Meanwhile, Sandy keeps Rebecca's presence in Newport a secret from Kirsten after deciding to take her case to court. Marissa and Alex's relationship intensifies, while Seth and Summer spend a lot of time together at Zach's insistence.

On Valentine's Day, Sandy and Kirsten's conflict about Rebecca continues. Ryan tries to make peace with Caleb in order to spend Valentines Day with Lindsay. Meanwhile, Seth, Zach, and Summer head to San Diego in hope to make their comic book idea succeed. But it all falls apart when Seth has a emotional breakdown and he ends up in a lonely state. Marissa and Alex decide take a step forward in their romantic relationship, while Julie returns from her trip to Paris in a vain and futile hope to reconnect with Marissa.

As Sandy continues working on Rebecca's case, Kirsten questions how strong their feelings are for one another. Meanwhile, Seth continues his downward spiral in the aftermath of Zach and Summer's night together, while Marissa tries to confront her fear about her relationship with Alex. Also, Caleb offers Lindsay a place in his family, but not without a paternity test.

Rain - and it seems there are as many problems as raindrops. Kirsten, Sandy...and Rebecca. Julie, Marissa...and Alex. Lindsay, Ryan...and Chicago. Summer, Seth...and Italy. Can't rain forever, can it?

The gang get the chance to have a few heart-to-hearts when they're accidentally locked in a mall for the night. Marissa and Summer catch up about the state of their current love lives, while Seth tries to help Ryan get over Lindsay's departure. Meanwhile, Julie receives a visit from a figure of the past, Alex questions her relationship with Marissa, and Sandy is determined to right his wrongs with Kirsten.

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 going do about her blackmailer and seeks some advice from Sandy. Also, Kirsten wants their editor, Carter, to stick with the magazine despite his reservations.

When Ryan's brother, Trey, gets out of jail and gives Ryan a call, the Cohens give him a warm welcome. Though, Ryan knows nothing good can come from it. Zach returns from his trip to Italy and gives some news that he has a new girlfriend which makes Summer curious and Seth is not really sure what to think. Meanwhile, after Julie admits her naked mistake to Kirsten, they both agree to get Caleb in on it for more help, unaware that Caleb as always, has a hidden agenda. Also, the Newport Living magazine is officially launched, but Julie's blackmailer, Lance, makes an appearance after Caleb had stiffed him for his blackmail money.

Sandy reluctantly agrees with Kirsten to serve as host/auctioneer at yet another OC benefit. Meanwhile, Trey lies to Ryan to prove that he can be self-dependent when he steals one auction exhibit leading Ryan and Seth on a mission to recover it before anyone finds out. Carter reinvigorates Seth and Zach's comic book dream, much to the annoyance of Summer. Also, Marissa moves in with the Cohens, unwilling to stand anymore of living with Julie or Caleb.

On Trey's 21st birthday, 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 rumble when one girl nearly drowns from a drug OD. Meanwhile, Seth is left in hot water by both Summer and Zach. Sandy wants to continue his friendship with Carter, leaving a confused Kirsten. Also, a distraught Julie shares some memories with her blackmailer Lance, and in the process learns a few things and gains a few ideas about the future of her marriage to Caleb.

Sandy, Ryan, and Seth devise a plan to save Trey from going to jail after he took the fall for supplying drugs at his birthday party. Kirsten and Carter, fulfilling more than their editorial duties, take a trip to Featherbrook's winery for a wine tasting party. Meanwhile, Caleb returns home from another long business trip and questions his marriage with Julie, and Seth, Summer, and Zach attend a party for the upcoming graphic novel.

Sandy, Seth and Ryan travel to Miami, Florida to visit Sandy's mother, the Nana, after she tells Sandy she is getting married to a much younger man. Back in Newport, Kirsten, unable go to Miami with Sandy because of work, is left on her own to deal with her feelings for Carter. Trey misinterprets Marissa's friendship as a sexual advance. Also, Zach invites Summer to a home-cooked dinner at his house.

Seth and Zach declare war when they compete against each other for Summer's affections. Meanwhile, Marissa is still reeling from being nearly raped by Trey, and refuses to confide in Ryan about the incident. Sandy confronts Kirsten when her drinking problem becomes very apparent. Also, Caleb hands divorce papers to Julie.

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.

Familiar faces show up for a final farewell to Caleb. Meanwhile, Sandy takes action to help Kirsten. And when Ryan learns about the Trey-Marissa incident, a showdown - if not a tragedy - is inevitable.

Ryan and Marissa deal with the aftermath of Trey's shooting. Kirsten meets Charlotte at rehab.

The new dean of Harbor School wants to expel Ryan and Marissa. Summer fights with Taylor over being Social Chair. Kirsten worries about leaving rehab.

Caleb's will is read. Ryan and Marissa are told to stay apart.

Public school? No problem. Marissa's glad to be at a school where no one knows about her. Oops. Everyone knows. Charlotte closes in on Kirsten. And Summer spies on someone lip-locked with Taylor.

Is Ryan shipping out? Sandy's mind-meld persuasion skills fail to convince him to stay. But where there's a will, there's another Cohen way. Charlotte now zeroes in on Julie; Summer outwits Taylor.

Party by night. Surf by first light. The Dawn Patrol beach blast is the backdrop for a developing Marissa-Johnny attraction. Meanwhile, Taylor has a crush on...Seth?! And Ryan again lets his fists do the talking.

Charlotte and Julie throw a faux-benefit. Taylor causes a rift between Seth and Summer. The tension between Ryan and Volchok comes to a head.

College applications are due, and everyone has to make up their minds about where to apply. But will their relationships survive this next chapter of their lives?

Marissa cares for an injured Johnny. But are they getting too close? Seth becomes insecure when Summer gets a higher score than him on the SATs.

Ryan, Marissa, Seth, and Summer raise money for Johnny's surgery by throwing Ryan a Bar Mitzvah.

Ryan, Seth, and Summer plot to get Marissa back into Harbor School.

Marissa's sister returns home from boarding school with secrets, lies, and a bag of stolen cash. Veronica and Julie compete for the affections of Niel Roberts. Johnny tries to distance himself from Marissa.

Julie throws Kaitlyn a birthday bash. Sandy tries to close a deal. Marissa butts heats with her sister. Seth spirals after being offered a college interview.

The Johnny-Kaitlin-Marissa-Ryan situation finds closure, perhaps, and tragedy for sure. Summer may be running out of forgiveness for Seth's half-truths. And Dr. Roberts makes a startling admission to Julie.

Kirsten and Julie throw a Valentine's Day party, as the community mourns the loss of Johnny.

Ryan and Sadie go on a road trip to look for Johnny's dad. A concerned Summer finds out about her dad's relationship with Julie. The police suspect foul play in Johnny's death. Marissa runs into Volchok.

The Cohens throw Ryan a party for his eighteenth birthday. Ryan can't decide whether or not to invite Marissa. Sandy tries to track down Dawn. Summer confronts Julie. Marissa crashes into an old memory.

Jess returns with news about Trey. Kirsten helps Ryan confront his savior complex. Seth and Summer receive sex counseling from Taylor.

Marissa's ties with Volchok send her into a substance abuse downward spiral. Summer is concerned about her friend--and the fate of her father's relationship if things don't improve. Ryan and Sadie's relationship is on the line, as Ryan and Marissa keep finding themselves intertwined in one another's lives. Seth spends some quality time with Kirsten, as she reaches nine months sober. The events at Newport Group turn violent.

College acceptance letters arrive. Three get in... and one doesn't.

Ryan heads to Albuquerque to invite his mom to graduation, while Summer tries to figure out why Seth broke up with her.

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.

On graduation day, Marissa is leaving to be with her dad, but Volchok has feelings for her and is angry at Ryan.

During the last days of summer before college, Seth is working at a comic book store in Newport. Ryan has problems dealing with the issues of the past and pushes himself with his new job. Kirsten is preparing Ryan a "care package" but neither she nor Seth can persuade Ryan to come home since he moved out after Marissa's sudden death. At Brown University, Summer settles into her new dorm room with new friend and roommate Che,who's an activist who wants to rally the students for a protest. Taylor phones Summer from the Sorbonne in Paris to ask about her current living status.

Six months after the earthquake, everyone makes decisions that will determine the rest of their lives.

On graduation day, Marissa is leaving to be with her dad, but Volchok has feelings for her and is angry at Ryan.

Familiar faces show up for a final farewell to Caleb. Meanwhile, Sandy takes action to help Kirsten. And when Ryan learns about the Trey-Marissa incident, a showdown - if not a tragedy - is inevitable.

Ryan and Marissa deal with the aftermath of Trey's shooting. Kirsten meets Charlotte at rehab.

Seth and Zach declare war when they compete against each other for Summer's affections. Meanwhile, Marissa is still reeling from being nearly raped by Trey, and refuses to confide in Ryan about the incident. Sandy confronts Kirsten when her drinking problem becomes very apparent. Also, Caleb hands divorce papers to Julie.

Time to move on: Jimmy decides to relocate to Maui. Time to make a move: Ryan and Lindsay wonder about a first kiss. Time to bust a move: Seth turns bad boy in an attempt to impress Alex.

Operation Protect Marissa! Seth and Ryan plan to keep Marissa from finding out about her mom's affair. It also becomes Operation Rescue Hailey when they inadvertently attend a Hollywood party where she's a stripper.

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 going do about her blackmailer and seeks some advice from Sandy. Also, Kirsten wants their editor, Carter, to stick with the magazine despite his reservations.

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

Engagement announcements are joyful news, right? Not when it means the one person Kirsten despises will become her stepmom. And not when Marissa will have a new family arrangement she doesn't want.

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.