Marco, a boy who admires healers who support warriors and heals all. In order to make his dream come true, he enrolls in a nursing school, "San Castello," which specializes in training healers. However, when he entered the school, it was a world where females were 90% and males only 10%! And what's more, contrary to the fun school life he hoped for, this school has various courses which will put his own life at risk! What fate will fall upon our plucky protagonist is...!?