Kiyoka raised her son Satoshi alone, but after he is bullied at school and stops attending, his adult classmate role-play friend Yusei appears to help him recover. Kiyoka is initially grateful for his kindness, only to learn that he masterminded the bullying and now demands money in return for protecting Satoshi. Once he discovers her vulnerability, he demands her mature body as well. Trapped by a secret she cannot tell her son, Kiyoka obeys him and inserts a vibrator between her legs as ordered.