It was Shiro who was born when Nanao was 20 years old. Nanao overcame the opposition of the surroundings and raised Shiro with one female hand. Because they were close to each other, they were closer to friends than to parents and children. When Shiro became an adult and his college life was settled down, Shiro invited Nanao to a hot spring trip. Nanao was in the mood for a trip, but Shiro had a desire to confess ...