In order to protect an ordinary businessman, Tsukasa Atsumi, from demons, a genius kunoichi, Shizuri Ideura, signs a master-servant contract with him on the condition that she stays with him….

The story centers on third-year high school student Jiro Yakuin, who gets saddled with his gyaru classmate Akari Watanabe for the class’s “marriage training” project about practicing to be a…