 Kristen s outgoing and spoiled younger sister Hailey Nichol, notorious for not doing anything with her life, returns home and asks to stay for New Years Eve. Although getting along fine with everyone, she shows her true colors when she throws a destructive New Years Eve party at the house when Sandy and Kristen are out and locks both Ryan and Set in the guest house. Meanwhile, Sandy and Kristen gets lost while traveling to a restaurant for dinner and find themselves in a rut, and out of their environment, at a swingers house party. The mysterious Oliver Trask, a charming young teenager whom Marissa met in the waiting room of her therapist, takes advantage of a mild quarrel between Ryan and Marissa to cast his spell on her and invites Marissa and her friends to his New Years Eve part at his parents  posh apartment penthouse. Also there in attendance are Summer and Anna who talk about Seth and decide to find him to make him choose which one of them he wants to be with.