Willie T. Stokes, a washed-up, alcoholic safecracker, has made a career out of posing as a department store Santa Claus every holiday season to rob shopping malls at night. Alongside his diminutive and foul-mouthed accomplice, Marcus, who plays an elf, Willie infiltrates department stores with a facade of holiday cheer, only to betray the establishments' trust by breaking into their safes. Despite Willie's deteriorating health, poor hygiene, and increasingly erratic behavior, the duo manages to execute their scam year after year, thanks in large part to Marcus's planning and Willie's safecracking skills.

However, this year's heist begins to unravel when Willie befriends a troubled and peculiar 8-year-old boy who believes Willie is the real Santa Claus. This unexpected connection starts to expose Willie to the possibility of redemption, challenging his cynical view of the world and forcing him to confront his own self-destructive behavior. Meanwhile, the mall's suspicious security chief is on their trail, closing in on their scheme. As Christmas approaches, Willie must decide whether to continue down his path of self-loathing and criminality or to embrace the chance for a better life that has unexpectedly presented itself.