This manga is about a woman who seems to be horny all the time on account of some mysterious force. The woman is cooking for a man I take to be her husband when suddenly an unseen entity begins to pleasure her. She attempts to stay quiet as she is satisfied so her husband does not notice. The manga skips suddenly to her sitting onto the toilet and having a flashback as to the origins of this thing. This shadow originated from her teasing a boy back in school, playing with his hopes. Eventually the boys shadow broke away from his body and merged with her shadow. The boy simply disapeared as if he never existed, but he seems to be stalking her through her shadow, protecting and molesting her.