There is a terrifying rumor circulating in Heiwu Middle School, that is, Gremory. Gremory is a book of witchcraft from ancient times, which records the secret marks of 72 devils noted by King Solomon. These magic marks contain the power of the devil. Anyone who has the ability to draw the mark can call out the devil represented by the mark. Solomon was the ruler of Israel in the 10th century AD. He possessed the mysterious power given by God and could control the devil. When Solomon died, Gremory also disappeared without a trace, but Solomon's descendant, the evil ghost Lester, made the Gremory reappear in the world. When Lester obtained the Gremory, he was immediately surrounded by exorcist masters from all over the world. In order to avoid the pursuit of the exorcists, Lester took the Gremory and hid in a school, where he quietly searched for the answers to the devil's secret marks, and that school was Black Martial High School. And she has a mysterious identity and walks into Heiwu Middle School with magical power. What will happen?