The story is about a demon king named Sadou Mao seeking to conquer the world of Ente Isla but, when confronted by the Hero Emilia, is forced to retreat through a gate that transports him to modern day Tokyo, Japan. To survive and find a way to return to Ente Isla, Satan gains part-time employment at a fast food restaurant called MgRonald-- Wikipedia.

Translated from the Japanese. "First published in 2011 by Kadokawa Corporation, Tokyo"--Page after title page.