You show up to work for the demon king expecting apocalypse and find instead a woman who wants you to help her optimize her sleep schedule. The gap between what Murin thinks this job is and what it actually becomes is the entire show, and it never stops being funny. A romance built on someone gradually realizing the person they've idolized is just as lost as they are, told through the smallest domestic moments, turns out to be way more satisfying than any grand demon conquest ever could.

Murin scores the perfect position as personal assistant to Beelzebub, the legendary ruler of Pandemonium whose fearsome reputation spreads chills at the mere mention of the name. Walking into the job starry-eyed, Murin quickly realizes his idol is nothing like the stories suggested. Beelzebub turns out to be a woman who runs the kingdom flawlessly at the office but loves fluffy things and needs help to get by once she steps away from work. Murin, who hates anything unprofessional, finds himself secretly charmed by her adorable behavior, and he learns that the other head devils of Pandemonium are not what they seem either. The result is a fantasy romantic comedy with a gentle slice-of-life pace.