Rinko, a wife lives with her husband's sister, Yu, who has been married for three years after their romance and has moved to Tokyo with the aim of becoming a cameraman. Yu is a bit younger than her Rinko and loves her like his own sister. One day, her husband decided to leave home for a three-day business trip. Under one roof there are only two sisters-in-law. Normally, women can live without worrying about each other, but there is a secret that no one can reveal. Yu has liked Rinko since the first day they met.