Gloria plans an American Christmas in a mountain cabin for the whole family. Cam and Mitchell work on a showstopping caroling performance. Phil is obsessed with his new sheepskin coat. They arrive in the mountains only to find it's warm. Haley and Andy worry about how they will keep their relationship a secret with the whole family there. Cam invites the mystery woman already at the cabin to stay for Christmas. Lily finds a locked mystery room and Luke and Manny try to scare her. Phil gives Andy a gift since Andy passed his realtor exam. Alex bonds with the mystery woman who is a professor at MIT. Jay announces he's retiring, but Claire is not his successor. Claire storms off into the woods and Phil comforts her with his sheepskin coat. Jay argues with Gloria about his test for Claire. Turns out he wants to give her the company, but he wants to make sure she wants it. Cam and Mitchell try to stop Lily's horrible singing by giving her a present early. Manny and Luke continue trying to scare Lily. After talking to the MIT professor for a while Alex decides to change. Everyone thinks Alex's attempts at holiday spirit are sarcastic. Claire confronts Jay and calls him boring. Lily screams after hearing sounds from the mystery room, and the whole family discovers Haley and Andy. Beth shows up right as the family is trying to figure out Haley and Andy. Phil takes Andy away and tells him to man up. Cam and Mitchell are incensed by Alex's beautiful rendition of Silent Night. Beth confesses to cheating on Andy with two other people, and she leaves. The whole family devolves into a fight which Gloria stops. Jay and Claire apologize to eachother, and Andy and Haley are together. The whole family shares a moment with snow falling. It turns out it's ash from a forest fire. Luke is left behind locked in the mystery room.