Human civilization no longer centers on fire; instead, it is now propelled by a dread of it. Recurrent wars have altered human biology, causing people to spontaneously ignite when they approach natural flames. Yet, a novel energy source keeps society from total ruin: a stone-like substance used to generate light and steam is found inside the bodies of monsters that plague many forests. The individuals assigned to gather this valuable resource are known as fire hunters. Touko, a young village girl, is rescued from a forest monster by a fire hunter who dies in the act of saving her. Once the hunter's dog, Kanata, recovers from his injuries, Touko's family sends her to the capital to return Kanata and the hunter's fire sickle to his relatives. Meanwhile, the fire hunter's son, Koushi, and his sister are taken in by a wealthy family. Koushi uncovers disturbing truths concerning the nation's ruling royal family. He undertakes clandestine research on a unique fire stone discovered by his deceased father, igniting a race against time between the country's leaders and those striving to save humanity from its final destruction.