Yuto Amagawa (voiced by Daisuke Hirakawa) is an introverted boy who lives alone. He only hopes to live the rest of his life in peace. However, things did not go as he wished. On his 16th birthday, a black-haired girl named Noihara Himuri (voiced by Ami Koshimizu) appeared in front of him, and a monster with a terrifying shape attacked Yuto. After the battle, Himuri told Yuto, who was still in shock, that he was a descendant of the "Twelve Demon Slayers". In the past, in a world where humans and demons lived together, demon slayers played a solid role as the guardian of mankind. But as time went by, their abilities gradually weakened, and eventually, most of the demon slayers drifted to the human world and became ordinary people. Today, the power of the demons seems to be making a comeback, so Yuto must muster up the courage to fight hard for the people he loves to be protected from harm.