Hiromi, who has never had a boyfriend, finds joy in setting others up. So, when her younger sister Riko starts dating someone for the first time, Hiromi decides to take charge and ensure their relationship thrives. However, as she searches for the perfect match for Riko, she stumbles upon an unexpected fact – Riko's heart beats for Nan, the school's well-known wooer. This realization poses as Hiromi's toughest test in her matchmaking endeavors.