The world after the final war of mankind. The land is covered by black forests, and people are invaded by human pyrophoric pathogens, whose bodies burn when they are close to natural fire. The fire in this world is collected by hunting the black beasts and fire demons that live in the forest. Among the fire hunters who hunt the fire demons, there is a rumor that has been whispered recently. "The fire hunter who hunts the artificial star wandering in the void, the millennium comet "Flickering Fire", is called the "King of Fire Hunters"... The protagonists of the story are Touko, a girl who grew up in the village, and Kouji, a former student of the capital. The fate of the two people will never change.