Kyoka is having an affair with a younger man. After passionately enjoying sex with her lover in a love hotel, she always makes it a habit to return home before it's time to prepare dinner. Today, too, she was indulging in phone sex with him at her house, passing the time in secret. That night, her son, who had skipped cram school, heard a strange sound from the other side of the door and, feeling suspicious, peeked inside. What he saw was his mother desperately thrusting fingers into her pussy, moaning uncontrollably. Beneath the surface of everyday life, hidden desires were stirring.