In the aftermath of humanity's last war, the world is shrouded in darkness with a black forest that has engulfed it. A deadly pathogen has infected people, causing them to ignite into flames when exposed to natural fire sources. The only source of safe fire can be obtained by hunting the Flame Spirits, which dwell deep within the forest. Lately, rumors have been circulating about "The King of Fire Hunters," an individual who possesses the ability to harness man-made stars such as the millennium comet that once roamed through space.
The narrative revolves around Touko, a girl raised in a village, and Koushi, a former student from the capital city. Despite not being intended to cross paths, their encounter will ultimately determine the fate of the world.