Newly hired teacher Satoshi Yabe begins his job teaching class 6-3 and soon becomes aware of the terrible Marui triplets: Mitsuba, Futaba and Hitoha. When the triplets notice Yabe might have a crush on the new school nurse, Aiko Kuriyama, they purposely try to injure his groin in the hope that Kuriyama will like what she sees. When Yabe incidentally gets injured after running into Kuriyama, she confuses him for a fourth grader (she's blind without her glasses)...