Hoping to bring his family closer together, Adam Gray arranges a vacation in a remote cabin on a snowy mountain. Things take a dark turn, however, when someone starts leaving gifts in the Christmas stocking mounted on the barn door.

Each morning brings something new, and with every passing day, the contents become more terrifying. Soon, the family makes a spine-chilling realization: they've been dragged into a deranged game of Secret Santa, and if they want to survive, they will have to fight.