Cai and Nanako met at a women-only SM club. As a customer, Cai took a liking to M Nanako and started frequenting the SM club. As they engaged in more play, they grew closer and decided to start a relationship. Although Nanako understood that Cai played with other customers, Cai's loneliness drove her to visit another SM club, which was found out by Nanako. With roles reversed from S to M, Nanako began to humiliate Cai with the same plays she had previously endured. Gradually escalating, Cai's body and mind became bound to Nanako.
