The story is set in Japan, 700 years after the age of swords and magic, where science has replaced magic. Social problems caused by magic and magical beasts are on the rise, and the Metropolitan Police Department establishes the Metropolitan Police Department's Magical Beast Control Division to deal with them. Kamishima Jingo, a werewolf (lycanthrope), is investigating a horrific case as a detective in the Magical Beast Control Division.

Meanwhile, the great elven sage Sajuel, who had been asleep for 700 years in preparation for the return of the Demon King, wakes up. However, the Demon King was resurrected and defeated 40 years ago. Sajuel is shocked to learn this, but he lends his wisdom to the Magical Beast Control Division and begins investigating with Kamishima and the others. A fantasy of magic and police unfolds.