Asta and Yuno are orphans who were raised together from birth after being abandoned at a church orphanage on the outskirts of the Clover Kingdom at the same time. In a world where everyone has the natural ability to perform a kind of magic, or a Magical Power (魔力 Maryoku), Asta is the only person born without any, leading him to train physically as compensation. Conversely, Yuno was born as a prodigy with immense magical power and the talent to control it. When they are 15, Asta and Yuno are granted the ability to become wizards known as Magic Knights by receiving grimoires, with which all magical power is channeled. Yuno is granted a wind-based grimoire held by the kingdom's first Wizard King, while Asta does not receive one. However, when a thief incapacitates Yuno to try and sell his grimoire on the black market, Asta summons his own grimoire, which contains the rare and mysterious Anti-Magic (enabling him to cancel out all magical effects), to defeat him. The story then follows the two boys in their time within separate squads in the Magic Knights, as they build a friendly rivalry to try and become the Wizard King themselves.