It's been three years since they got married. Yui, a wife, is busy taking care of her husband who suddenly fell ill. Her brother-in-law Koji, who secretly adores Yui, worries about the future of the couple, but is powerless to do anything... One day, when Koji comes to visit as usual, he comes across Yui satisfying her brother's sexual desire. Koji is fascinated and secretly peeks in. Furthermore, Yui is lonely because she can't have sex with her husband, so she comforts herself alone in her room. Koji can't suppress the lust welling up inside him...
