After failing her university entrance exam, Hino Miharu had no choice but to search for a job. For the past three years, she’s been working part-time at a convenience store, where she’s scolded by her manager and taken advantage of by her younger co-worker.
After working a horrible shift on Christmas, Miharu steals an expired cake from the store and finds a horumon stall run by a mysterious man in a black Santa outfit. He explains that there’s two Santas: the red one that gives gifts to good kids, and the black one that takes care of the bad kids. Miharu is then given an outrageous job offer to be the Black Santa Claus’ new employee!!