After fleeing from Rumble Town, Seth, Doc and Melie are back at the Artemis Institute. Thanks to Alma, Seth learns more about Piodon, his mysterious brother. But the quest for the Nemeses mythical nest Radiant has already waited too long, so the Horned Boy and his friends head to the island-continent of the Wizard Knights.

This location may be a new city for audiences, but it's a decaying world that's falling apart! Not only must Seth deal with these hardships, but he must also face a personal phenomenon where visions are invading his mind a little more each day.

Seth, a Sorcerer from Pompo Hills, sets out on an adventure to exterminate all these Nemeses. Accompanying him are Doc and Mélie, fellow Sorcerers who share his ideal. Their main objective is to bring about a world where Sorcerers are no longer persecuted for being infected, and to that end, desire to destroy the source of the Nemeses themselves: the mythical Radiant.