Nagasawa Azusa plays a married Milf whose son, Tarou, has a twisted habit whenever his father is away on business: sneaking into his mother's bathroom to spy on her naked. Though she's aware of his actions, she dismisses it as typical teenage curiosity. One day, as Tarou creeps toward the bathroom as usual, she calls out, "Let's bathe together," inviting him in. Overcome by shame yet visibly aroused, Tarou enters with a bulging erection. Seeing this, the mother maintains her calm demeanor, acting as if nothing unusual is happening.