After the death of her husband, stepmother Shizuka began living alone. Concerned about her low spirits, her daughter and son-in-law decided to move in with her. While their cohabitation started smoothly, the son-in-law found himself increasingly tormented each day, captivated by his stepmother's charm. He couldn't stop fantasizing about her in his daily life. One day, returning home early, he learned his wife had gone shopping and suggested taking a bath together with Shizuka. Though initially reluctant, she gradually gave in, drawn to his gentle yet strong demeanor. Her emotions began to stir, and as she became aware of his feelings, her heart slowly started to change.