Kensuke Satou

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. Ikoma, a boy who lives in the Aragane station and helps to build Hayajiro, creates his own weapon called Tsuranukizutsu in order to defeat the creatures. One day, as he waits for an opportunity to use his weapon, he meets a girl named Mumei, who is excused from the mandatory Kabane inspection. During the night, Ikuma meets Mumei again as he sees Hayajiro going out of control. The staff on the locomotive has turned into the creatures. The station, now under attack by Kabane, is the opportunity Ikoma has been looking for.

Toru Acura is a 20-year-old retired soldier meandering through life now that the war has ended. He encounters Chaika Trabant, a 14-year-old sorceress carrying a coffin, and follows her in hopes of finding meaning to his life again. The two travel with Toru's adopted sister, Akari, the employed member of the group and thus Toru's source of income.

Chihaya Ayase is a frank and ebullient girl who becomes fascinated by the obscure world of competitive karuta, a card game based on Japanese poetry. Introduced to the aggressive style of the game by a quiet and thoughtful elementary school classmate named Arata Wataya, the two quickly become close friends. They start playing as a group with Taichi Mashima, Chihaya's smart and athletic childhood friend, until they have to part ways during their middle school years due to several circumstances. As their high school life begins, they meet once again.