Ai, who is a female teacher and the advisor of the swimming club, has only one time when she can let Kokoro go free. It is at the pool at night after club activities are over. Wrapped in the silence of the night and a wet competitive swimsuit, Ai feels a pleasant tiredness and does not want to go home to her husband, so she masturbates in the locker room. However, she is seen by a delinquent student... The student goes wild, unable to stop at her voluptuous breasts spilling out of the competitive swimsuit. Ai did not know at that time that the pleasure of being raped would dominate Ai at night...