As the world is in the middle of an industrial revolution, a monster appears that cannot be defeated unless its heart, which is protected by a layer of iron, is pierced. By infecting humans with its bite, the monster can create aggressive and undead creatures known as Kabane. On the island Hinomoto, located in the far east, people have built stations to shelter themselves from these creatures. People access the station, as well as transport wares between them, with the help of a locomotive running on steam, called Hayajiro.