In a world where magic exists and there is some social inequality among people who can do magic and no. Louise Françoise Le Blanc de La Valliere, also known by his peers at the academy of magic "Louise the Zero" (ゼロ の ルイズ, Zero no Ruizu?), Because she is unable to make any spell without an explosion . In academia there is a ritual by which all call his "family" (to accompany the child wizard and will serve you for the rest of his life), Saito and Louise summons a being of the Earth (Japanese) be a big deal because he had never seen anyone convene a commoner "person without mastery of magic" Which surprises everyone because it acquires as a "family" the ability to use weapons by just touching them deftly.