After her divorce, her mother raised her son alone. One day, after he had grown up and found a job, she planned a trip to a hot spring for the two of them to spend some time together during her son's vacation. Before she knew it, her son's feelings for his beautiful, young mother had been distorted... "I love you, Mom..." Hibiki was shaken by the sudden confession. Unable to contain himself, the son approached his mother. As the pleasure built up within him, perhaps he had actually been hoping for this to happen. Hibiki herself also sought sexual pleasure... Mother and son seek each other out in Joshu-juku...