Oliver Horn enrolls at Kimberly Magic Academy skilled with both wand and blade, and pairs off with Nanao Hibiya, a headstrong samurai transplant from the distant nation of Yamatsu, as the two become rivals and allies moving through the school's monster-filled labyrinths. Beneath the ordinary-student act, Oliver is hunting the mages who killed his mother, and Kimberly's halls hide exactly the kind of danger, and the kind of targets, his revenge requires. Their first year is where that dual life starts to collide with the school around him.