At Tristain Academy for young mages, Louise is derided as 'Zero' for never completing a spell correctly, until her familiar-summoning ritual drags Saito Hiraga out of his ordinary life in Japan and into Halkeginia. Magically bound as Louise's familiar, Saito serves the short-tempered noble while the two navigate court politics, rival students, and Saito's growing role in the kingdom's defense. This original light novel series is the source material behind the manga and anime adaptations, spanning Louise and Saito's story across the greater conflicts of Halkeginia.