One day, Midori Nashiro returns home from shopping and finds her son asleep, having not cleaned up after masturbating. Despite his sulky demeanor, she genuinely feels joy seeing how adorably he has grown. However, catching the scent of semen from a tissue she accidentally touches, impure fantasies flash through Midori's mind. Unable to suppress her lustful desires, she begins touching her son's crotch. Soon, driven to turn her lewd fantasies into reality, she heads toward the bathroom where her son is taking a bath...