Billy Chapman, who was traumatized by his parents' Christmas Eve murder, then brutalized by sadistic orphanage nuns, grows up to dress as jolly St. Nick for a yuletide rampage to punish the naughty.
Two childhood friends who have since become fierce rivals are forced to make nice when their children marry. But the feud reignites when a bundle of joy arrives, and the feisty grandmothers vie for baby-tending duties when the new mom goes back to work.
Ricky is released from a mental hospital, taking with him the memory of his brother Billy's death and embarking on a journey of relentless revenge.