This is an anime adaptation of a popular manga based on a fictional world with medieval technology. In this world, humans coexist with creatures called Yoma. The Yoma are sentient, shape-changing monsters that disguise themselves as and then feed on humans. By consuming a human brain, the Yoma can absorb the victim's memories, allowing them to infiltrate human circles without arousing the suspicions of their victim's close friends or family. In order to protect humans from the Yoma, a secret organization has created an order of superhuman warriors known as Claymores.