The world is overrun with monsters called Nemeses-and a young boy infected by one will stop at nothing to defeat them all!

Seth is an aspiring wizard living in a pastoral village under the watchful eye of his mentor. Like all wizards, he is an "infected": one of the few living creatures that has survived contact with one of the Nemeses, creatures fallen from the sky that contaminate all they touch. His apparent immunity led him to choose a path that seemed to be perfect-to become someone who hunts and fights Nemeses. But Seth longs for a quest that goes beyond the simple hunt for monsters. He wants to find their home, Radiant. Along with other wizards, he travels the world in search of Radiant, under the sinister eye of the Inquisition...

Seth finds himself face-to-face with a man named Picodon, who claims to be Seth's brother. Picodon came to Rumble Town to watch the destruction, but upon finding Seth, offers him something to help with his infection. Meanwhile, Grimm and Melie continue trying to prevent Hameline from destroying Rumble Town.