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..