Ryoko is a married woman living in an apartment in Tokyo. She has a problem. Her husband has recently become cold towards her. She suspects that he is having an affair with Yumi, a married woman next door who is constantly having affairs. As if to mock Ryoko's jealousy, Yumi seduces Ryoko's husband, Yukio. When Ryoko finds out, she takes revenge by seducing Yumi's husband, Shigeru.