When his dysfunctional family clashes over the holidays, young boy is disillusioned and turns his back on Christmas. Little does he know; this lack of festive spirit has unleashed the wrath of Krampus: a demonic force of ancient evil intent on punishing non-believers. All hell breaks loose as beloved holiday icons take on a monstrous life of their own, laying siege to the fractured family's home and forcing them to fight for each other if they hope to survive.