Our protagonist lives in the same apartment complex as his childhood friend and her single mom. The mother gives away an air of elegance and modesty, a typical housewife.
What she keeps well hidden is the fact that she's a complete masochistic pervert who steals dirty underwear and used tissues from our protagonist's trash and uses them to frequently masturbate. In this doujinshi we see what happens when her libido goes completely out of hand and she decides to let our protagonist know what exactly she wants him to do to her~