Zetsuze Ai, a mutant who has mouths in both of his hands, is in love with his co-worker Kanzaki. One day, he finds out that she is also a mutant and asks her to go out with him, but she draws a line between them and rejects him. Zetsuze refuses to give up, uses a sort of blackmail, and ends up in a physical relationship...!? Who is she really, and why does she strongly insist on “absolutely no kissing”?