A self-proclaimed psychopath, coldblooded lawyer Ninomiya becomes obsessed with stopping an ax-wielding serial killer who's made him their next target.

Norio and his girlfriend, Mari Tanabe, have been dating for three years. They lived a peaceful life until one summer day, where Norio comes home to experience a peculiar sensation. The moment he sees the strong sun rays shining into his apartment, he realizes that Mari isn’t there. Instead, he finds an unfamiliar-looking woman who tells him that she is here to live with him. The eerie pale-skinned woman then introduces herself as Mari..

Fifth grader Kei Watanabe has inherited the hunter's blood to hunt yōkai. To save the world from destruction, Kei challenges a war against the yōkai.