Kyouichi's indecisive character has led him to repeatedly commit the foolish mistake of adultery. One day, Imagase, a college classmate he hasn't seen since graduation, shows up as the private detective hired by his wife to investigate his infidelity. Imagase, however, proposes a deal. He won't tell Kyouichi's wife about his affairs, but, for compensation, he makes an unbelievable demand: "I want your body in exchange..."

In the second edition, there is an extra chapter.