JUL-557 Husband goes on a business trip, wife calls her girlfriend over for some lesbian fun.

Rinko, a wife living with her husband's younger sister, Yu, who has been married for three years after a romantic relationship, moved to Tokyo with the goal of becoming a filmmaker. Yu is a bit younger than Rinko and loves her like her own sister. One day, Rinko's husband decides to leave for a three-day business trip. Under one roof with only the two sisters-in-law, it is common for women to 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.