His stepmother, Reina, is kind, beautiful, and busty. Kouji is proud of her mother, but she has a secret. She has a severe addiction to big dicks, and whenever she sees a big dick, she goes completely out of control, an outrageous sexual fetish. If this sexual fetish were to come out, their family would fall apart. Reina lives her life with the utmost caution. But one day, when she sees her stepson adjusting his penis position, she realizes something. "That boy...he definitely has a big dick!"