Kokoro was married to a kind husband and lived a happy life. But one day, her husband's father, who she hadn't heard from in a while, came to visit. Her husband resented his father for abandoning their mother and causing them so much trouble. However, with the encouragement of her kind-hearted father-in-law, who had nowhere to go, she decided to let him stay with her for a week. However, that was the beginning of her mistake...