The husband, wife, and the wife???s sister live together in one house. The husband and wife appear to have a normal relationship, but the wife is secretly having an affair. Meanwhile, the husband develops feelings for his wife???s sister, and they also begin an affair. The husband plans a birthday party for his wife and invites his boss. When the boss arrives, the wife is shocked to see him because he is the same man she is having an affair with. The wife privately asks the boss not to tell her husband about their relationship, but the husband overhears everything and reveals that he already knows the truth. This leaves the wife completely shocked.