Despite being 11-year-old triplets, the Marui siblings have distinct personalities. Mitsuba is the eldest and acts beyond her age, enjoying inflicting harm on others. Futaba is athletic and strong, possessing a twisted side. Hitoha is the youngest, exhibiting a sweet demeanor, but capable of turning into the most dominant, twisted, and sadistic of the three when provoked. All three siblings share the same class with their newly graduated teacher, Yabe Satoshi. Despite being ordered around and humiliated by the girls, the triplets attempt to create a relationship between Yabe and the school's incompetent new nurse, Kuriyama Aiko. However, Yabe is not interested in Aiko, and their unorthodox approach to matchmaking creates chaos.