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.

The episode was rated 7.88 from 292 votes.

"I love the Vegas," Seth says. But Seth is a player who's played when he, Ryan, Sandy and Jimmy hit the gambling town for what's presumed to be Caleb's bachelor bash. And claws are out when Julie and Hailey attend the Newport bachelorette party.

The episode was rated 7.88 from 209 votes.

Luck is in the house during a Vegas night fundraiser; Seth becomes Summer's lucky charm and Marissa reconnects with Luke. In the aftermath of events involving Ryan's mom, Kirsten takes a chance and opens her home to the boy.

The episode was rated 7.89 from 344 votes.

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.

The episode was rated 7.90 from 213 votes.

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.

The episode was rated 7.98 from 273 votes.

Julie wears out her welcome with Caleb: true. Seth thinks Summer's hot: true. Oliver is crazy-mad about Marissa: true. Now sure of it, Ryan races against time to keep Oliver from hurting himself or Marissa.

The episode was rated 7.98 from 231 votes.

When Ryan is faced with being shuffled into the child-services system, Seth comes up with a plan: Ryan can secretly live in an unfinished home owned by Seth's mom. It's a foolproof plan - for a while.

The episode was rated 7.99 from 361 votes.

What happens in Mexico stays in Mexico. But the secrecy surrounding a summer's-end teen trip to Tijuana can't stop Marissa from feeling the way she feels when she sees Luke with Holly.

The episode was rated 8.00 from 301 votes.

Calculus. AP Enlgish. 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.

The episode was rated 8.01 from 302 votes.

Used to be Seth couldn't find a girl. Now he has two - Anna and Summer show up for Thanksgiving. Ryan also has double trouble, as he and Marissa visit his old neighborhood and encounter an ex-flame.

The episode was rated 8.01 from 270 votes.

It's part Christmas, part Hanukkah and totally a Cohen-family way to celebrate the holidays. But a time out for the holidays doesn't mean time away from Marissa's personal problems or Caleb's business tactics.

The episode was rated 8.06 from 279 votes.

Ryan promised to stay out of trouble. But trouble finds him as he, Seth, Marissa and others take part in one of the biggest events on the Newport social calendar: the Debutantes Ball.

The episode was rated 8.07 from 325 votes.

As the New Year looms, Ryan doesn't know how to respond when Marissa says those three meaningful words. Sandy and Kirsten are wallflowers at a swingers' party. And at home, Seth thinks of what might have been.

The episode was rated 8.16 from 254 votes.

Summer is near and that means sun, surf and rejuvenation. Or to Ryan, Seth and Marissa, it may mean none of the above as each faces a critical crossroad. Just the same, Newport society rises to the occasion when Caleb and Julie do the "I do."

The episode was rated 8.22 from 220 votes.

Just a freeway's drive away. And yet worlds apart. Rejected by his parents after a brush with the law, Ryan Atwood moves temporarily into the pool house of his attorney's posh Newport Beach home...and finds both friends and foes among the privileged O.C. youth.

The episode was rated 8.24 from 463 votes.