Izumi is a mother who lives with her son in the house left by her divorced parents. One day, she is harassed by her husband who keeps coming to her for money even after the divorce, but she is saved by Shimizu, who works at a renovation company. Izumi, who is a good-natured person who doesn't know much about the world, becomes close to Shimizu and even gives in to his desire to have sex with him. After that, Izumi accepts Shimizu completely, even letting him help her with her son's studies, but the words of her husband, "Be careful of Shimizu," that she says to him when he leaves, are stuck in her mind.