Corey Price

When Seth visits Summer at Brown, he finds an empty dorm room. Meanwhile, Sandy and Kirsten take advantage of an opportunity to bond with Ryan, who is in a Taylor-induced haze.

In the fourth season premiere, everyone struggles to adjust to life without Marissa.

Ryan travels to Mexico, with a stubborn Seth in tow, to put an end to his turmoil in the only way he knows how, but he comes up short in his quest for revenge.

Newly engaged Seth and Summer both panic about the prospect of being married, but neither will break it off, despite the advice of their friends.

As the Cohens prepare for Kirsten's 40th birthday party, Kirsten gets some news that will change her life forever.

Taylor's ex-husband, Henri-Michel, gets a little too close to home while promoting his erotic memoirs, causing Ryan to question his own relationship with Taylor.