Yui Hatano and her husband move to a new town due to his job transfer. They greet their neighbors below, the Otsuki couple, who invite them over for dinner and drinks. While intoxicated, Yui is taken by force. That night, she's carried into the bedroom and taken by Mr. Otsuki. This single encounter awakens her desire for sex, despite her guilt toward her husband. Meanwhile, Mr. Hatano also succumbs to Mr. Otsuki's advances, beginning a physical relationship. The fates of the two couples grow increasingly entangled...