Siki Itinose — a teenager from the 21st century. In his veins runs the blood of demonic beings who once terrorized humanity. In our time, the descendants of a brave boy-warrior have united into the Momotaro Agency, which hunts Siki and others like him. After a battle with these 'People's Avengers,' Itinose learns the secret of his father's death and decides to answer the call of his blood. He enrolls in an academy for descendants of demons, where one can develop superpowers and strike back at killers who cloak themselves in a connection to the legendary hero.