The story takes place on the continent of Sandis, a world of swords and magic where horse-drawn carriages are the only means of long-distance travel. Mark, a young blacksmith living with his beloved younger sister Milady in the rural Tarto Village, one day catches a suspicious man following her. The man is Rock, a railway enthusiast from modern Japan who has been mysteriously transported to this world. Mistaking Rock for a threat, Mark subdues him, but soon learns Rock is simply trying to find a way home.

Their encounter coincides with the awakening of a golem, an ancient demon weapon that had been dormant for two hundred years. To protect Milady and their village, Mark and Rock join forces with Primera, a student from the Royal Elusion Magic School, and the boar-like Ino tribe. Rock's extensive railway knowledge proves unexpectedly useful, and he devises a plan to mount a cannon on rails, creating a makeshift railway gun to defeat the golem. This success demonstrates the potential of railways in a world that has never seen them.

Encouraged, Mark and Rock begin laying tracks and building rolling stock, using a special ability called Iron Creation to manifest metal components. They construct a steam locomotive, transforming the kingdom of Elusion. The railway quickly revolutionizes transportation and commerce, leading to unprecedented development. Their work attracts the attention of other beings, including the tiny Lilliput people, whose sacred ritual is disrupted by the tracks laid through their forest. Mark and Rock must negotiate with them and deal with a dragon deity angered by the interruption.

As the railway network expands, a new threat emerges from the魔族 (demon race). Their leader, the Demon Lord, is revealed to be Takako, a high school girl Mark once saved from falling onto the tracks when he worked as a station attendant in his previous life. The second prince of Elusion, Kailain, who has been wandering the continent and understands the demon army's ambitions, returns to the kingdom. He proposes a grand plan to extend the railway across national borders and complete a continental loop line. This loop line, Kailain believes, could create a portal back to Japan, fulfilling Rock's long-held desire to return home. The story culminates in a final confrontation with the demon forces, with the railway serving as both the catalyst for the kingdom's prosperity and the key to resolving the conflict.