Asta and Yuno were abandoned together at the same church, and have been inseparable since. As children, they promised that they would compete against each other to see who would become the next Emperor Magus. However, as they grew up, some differences between them became plain. Yuno was a genius with magic, with amazing power and control, while Asta could not use magic at all, and tried to make up for his lack by training physically. When they received their Grimoires at age 15, Yuno got a spectacular book with a four-leaf clover (most people receive a three-leaf-clover), while Asta received nothing at all. However, when Yuno was threatened, the truth about Asta’s power was revealed, he received a five-leaf clover Grimoire, a “black clover”! Now the two friends are heading out in the world, both seeking the same goal!

The film’s story begins when Arata inadvertently touches “Hermes Apocrypha,” Lilith’s Grimoire. Suddenly, he is enveloped by a bright white light, and a girl appears before him. She calls herself Lilim, and treats both Arata and Lilith as her parents. At the same time she appears, something changes in the world. The forbidden Eternal Library awakens. In the Library is sealed the ultimate culmination of Alchemy, the White Demon Lord. The White Demon Lord plots to eliminate Arata and the Trinity Seven to usurp the position of Demon Lord. Bristling with untold power, the White Demon Lord attacks Arata, and triggers a desperate crisis where Arata and the Trinity Seven must save the world in this last battle.