A young man named Eric apparently dies in a suspicious house fire after saving his girlfriend, Melody. One year later, a new mall is constructed atop where Eric's house once stood, where a shadowy, uninvited guest is preying on the mall's crooked developers.

After a man dressed as Santa Claus brutally murders Billy Chapman's parents, little Billy then endures the cruelty of a sadistic nun at his orphanage. Years later, when adult Billy has to fill in for an absent in-store Santa, his childhood trauma brings him to the breaking point.

After witnessing his parents' brutal murder on Christmas Eve, Billy transforms into a Killer Santa, delivering a yearly spree of calculated, chilling violence. This year, his blood-soaked mission collides with love, as a young woman challenges him to confront his darkness.