One day, her son brought his friend Kosuke home. Bored with her monotonous daily routine, her mother Mariko happened to see his erect penis and became aroused, so she decided to have a snack to kill time... Unable to resist his insatiable sexual desire, she ended up being violated countless times. Since then, Kosuke has been obsessed with the adult charm that oozes from him, and has been visiting her almost every day since then. However, Mariko has reached her limit with his bottomless sexual desire, and finally...