The virus arrived without warning. Turning the bitten individuals into 'Corpses;' ravenous, blood-hungry beings. The turned individuals sought only to attack and drain their victims and move on. Veins glowing as though made of magma, the hearts of the Corpses were protected by a resilient iron cage, impervious to all but the most grievous of harm.

Years later, some cities and towns managed to retreat within high walls and spiked borders, housing the survivors of the ongoing plague. All the settlements were connected via railways, on which refitted trains now dared to travel, often at great cost. When survival is predicated on self-sacrifice, casualties are a guarantee.

When the survivor of an overrun station finally escapes, he finds that hope hasn't been destroyed completely. A small, elite group seeks to bring back the burning desire to live life to the fullest. To rekindle the hope that once spread across all lands.
But everything has a cost.
(Takes place in the universe set by Kabaneri of the Iron Fortress, (Kōtetsujō no Kabaneri))