Kirsten's rebellious sister causes turmoil by hosting a huge party in the Cohens' house on New Year's Eve. Marissa goes to another party, but Ryan rushes to kiss her at midnight.
Disruptive Hailey refuses to leave the Cohen house. Seth chooses Anna. Ryan is jealous of Marissa's troubled new friend, Oliver. But Ryan later helps Oliver get out of trouble.
Summer tries to annoy Seth and Anna. Oliver irritates Ryan. When Oliver almost overdoses, Marissa stays with him. Hailey moves out. Jimmy and Sandy go into business together.
Marissa tries to reconcile with Ryan, but he can't forgive her for Oliver. Ryan's ex-girlfriend from Chino arrives for Valentine's Day. Seth and Summer escalate their friendship.
Summer loves being with an actor (COLIN HANKS), to Seth's chagrin. But Summer minds when Seth meets a sexy girl (PARIS HILTON). Ryan hides Luke and Julie's affair from Marissa.
