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. Despite her cool appearance of defeating demons, Shizuri is an otaku NEET who spends all her time playing video games. While Shizuri is spoiled by Tsukasa and leads a lazy cohabitation life, the quirky Kunoichi gather together.
