The protagonist Lee Seul (Kim Hye-soo) is an optimistic housewife who will not panic even if she encounters a big event that comes out of the blue. She is now secretly dating a college student (Lee Min-ki) who is ten years younger than her and is extremely kind and simple. Xiao Niao (Yi Jin-hee), a married woman with an S-shaped figure, who seems simple but is extremely restless inside, is not a person who keeps to herself. She is dating two foxes who are regarded as myths in the securities industry like close friends, and of course, eating forbidden fruit is inevitable. The different black hearts and desires between each other do not affect their romantic progress. Their boring life can only be reconciled with the vitality stimulated by the illicit love, but if the fox's tail is too long, it will inevitably be discovered or cut off, otherwise it will get in the way. In order to achieve a perfect affair, an earth-shaking and unexpected turmoil is approaching, and their love history is uncontrollably heading towards the vortex of that turmoil. Behind the scenes: There is no such thing as a good day for an affair. In this era where shamelessness is considered cool, whoever falls in love with whom will go to bed. This is something that everyone knows. This film is not a road movie like "On the Way to the Racecourse" or a movie like "Secret Love" where you can enjoy an unethical love anytime and anywhere. Director Zhang Wenri, who once filmed "Happy Doctor Zhang", has spent eight years grinding his sword to launch a new work "A Good Day for an Affair". It is just a comedy about two couples who have an unethical affair. "A Good Day for an Affair" does not want to sell it with gimmicks such as explicitness and promiscuity. On the contrary, its eyes are more gentle and delicate, because this is a story about people who pursue ultimate happiness. How to tell the story of two adulterous housewives in a gentle and understandable way, a topic as heavy as the issue of death, was the biggest difficulty, but Director Jang did it, and once again demonstrated his extraordinary talent in "Happy Doctor Jang", making the film beautiful. The participation of stars such as Kim Hye-soo, who became the top actress with her outstanding performance in "Tazza", and Yi Jin-hee, who has unlimited potential and can play any role in films such as "The Most Beautiful Week of My Life", will undoubtedly make the film more outstanding.