Dantalion, one of the many candidates for Lucifer's throne, decides to live in the human world an attend William's school and lobby the young noble to choose him as Hell's ruler, but he gets more than he bargained for when William's friend Isaac accidentally summons one of his competitors!

It's family visiting day at the academy, but with his parents long dead and Kevin treating him like a stranger, William is feeling down. His mood quickly changes when the father of fellow prefect Swallow invites him to dinner, and the boy himself insists he wants William to "meet my parents."

Hoping to win the prize for best event at Stradford's school festival, Wlliam orchestrates a culinary showdown between Dantalion and Sytry's respective butlers, Baphomet and Leonard.