The Yamamotos are a happy couple with a good relationship. On the surface, they seem like any other ordinary couple... but their nightlife is exactly that of "master" and "slave." Miwako, the wife, feels her husband's love through their abusive sexual acts, and thinks she can do anything for him. Then, one day, Miwako receives a sudden proposal from her husband. "I want to test whether your love for me is real! Can you promise me that you won't cum even if you have sex with a man other than me?"