It was in our time, Tokyo had big and lofty buildings to the skies and the noise of the city. People did not know that demons existed in this world, as they believed that these were just legends. A secret organization of "Demon Slayers", they protect people from demons in secret so that people do not know about them and live in peace. But everything changed when the girl decided to turn the corner and shorten the way home, she looked in fear at the demon who wants to eat her. Everything happens as if on a click and the demon's head falls and it decomposes. She sees two tall men in front of her, one with a katana and the other with two large blades.