France, 15th century. Michel de Nostradamus, Europe's most famous prophet, received a strange letter, wrapped in a secret, from his old friend Gregory. The latter asked him to come to him as soon as possible. Upon arrival, he discovered that evil spirits had cursed his friend's house. After performing an alchemical ritual to free the house from the spell, Nostradamus saw visions of four horsemen who would come to destroy our world.