In a world where humanity fears fire due to a biological change that causes spontaneous combustion, society relies on a stone-like material within forest monsters for light and steam production. Fire hunters, tasked with gathering this essential resource, play a crucial role in maintaining order. When a young girl named Touko is rescued from a forest creature by a fire hunter who sacrifices himself in the process, she embarks on a journey to return his belongings, accompanied by the hunter's loyal dog, Kanata. Simultaneously, the hunter's son, Koushi, and his sister are taken in by a wealthy family, leading Koushi to uncover unsettling truths about the ruling royal family. As Koushi delves into his late father's research on a unique fire stone, a race against time ensues, pitting the forces seeking to preserve humanity against those in power.