Hotaru has been married for over thirty years, and her only son, Kenji, has successfully become an adult and entered society. One night, while in the bathroom, Kenji noticed his mother's pubic hair and became overwhelmed with uncontrollable excitement. He began masturbating while fantasizing about receiving handjobs from her and ejaculating onto her pubic hair. Meanwhile, Hotaru accidentally witnessed her son masturbating and, seeing his erect penis for the first time in years, felt long-forgotten desires stirring within her once again.