In a few days, the world plunged into the Middle Ages. The force unknown to humanity threw its technological development back a thousand years, changing the properties of many chemical elements. This book describes an atypical apocalypse, where heroes will have to learn to survive in a new world, a world without kindness and humanity, without all the gifts of civilization, in a world where cannibalism, slavery and obscurantism are again emerging... in a world where brute force and the Sword rule again!