One day, an ordinary college student, Yuuhi Amamiya was asked to save the planet by a talking lizard. Before he even got the chance to refuse, he was chosen as a member of the Beast Knights, received the power of Domain Control through a mysterious ring, and was forced to fight for his life. However, right when it all seems lost, Yuuhi was saved by the girl who lives next door, Samidare, who, much of his surprise, was also plotting to destroy the planet herself. As a result, Yuuhi, charmed by her overwhelming strength and charisma, became her servant and joined her on her quest to destroy the planet.