Erika remarried a man 10 years older than her. The three of them started building a new home together, including her husband's son from a previous marriage, Tatsuya. Erika quickly got along with Tatsuya, who was close to her age, and thought they had become a happy mother-son pair. But because of their closeness, Tatsuya began to think of her as a woman. While her husband was away on a business trip for a week, the relationship between the stepfather and stepdaughter became complicated...