Punch Line is an erotic visual novel in which the main character is a high school student who faints at the sight of women's panties. Yuta Iridatsu becomes the victim of a strange event — his soul is separated from his body, after which he becomes a ghost. To return everything as it was, the character must find a special book, but, by a strange coincidence, it is located in a house inhabited by young girls. During his journey, the hero will be helped by a ghostly perverted cat. If the hero sees the charms of the girls, he may become overexcited, which threatens a real apocalypse on Earth.