One day, unremarkable college student Yuuhi Amamiya meets a talking lizard who asks for his help saving Earth from a crisis. Before he can refuse, Yuuhi is turned into a member of the Beast Knights and given a ring that gives him the psychic power “domain control.” He is then immediately attacked by an enemy! But just as all seems lost, he’s saved by the girl next door, Samidare. But it turns out Samidare isn’t really a savior of any kind… she’s actually a demon lord who wants to conquer Earth! Drawn to her absurd strength and evil charms, Yuuhi becomes her devoted servant and acts to support her wicked schemes.