On the island country of Hinomoto, the hayajiro Kōtetsujō, an armored train, is attacked by several Kabane, humans transformed into undead creatures by a viral infection, and the bushi defeat them. However, a bushi is bitten and he commits suicide to avoid being killed as a Kabane. At the train's destination, Aragane Station (顕金駅), Ikoma, a steamsmith, is working on a powerful piercing gun to kill the Kabane. The Kōtetsujō arrives at Aragane Station and Ikoma steals some Kabane body parts...