They thought they had become a close family... Yuri married a man much older than her. Her husband remarried and his child from a previous marriage, Tatsuya, was living with them. They were close in age and Yuri thought they had become like brother and sister, able to talk about anything freely. But Tatsuya, on the other hand, has feelings for Yuri as a woman. Yuri and Tatsuya, who have a delicate relationship, end up spending a week alone together...