Three years have passed since Rinko, a wife who married her workplace romance and lives with her husband's younger sister, Yuu, who moved to Tokyo to become a photographer. Yuu is a little younger than Rinko and she Ke'ai on her like a real sister. Then, one day, her husband has to go on a business trip for three days, leaving the two sisters-in-law alone under the same roof. Normally, they could live together as women without worrying about each other, but Yuu has a secret that she can't tell anyone. Yuu has had feelings for Rinko since the first time they met...