Technology has advanced due to the discovery of an alternative source of fuel called "Thunder-Cores." This has changed civilization for the better due to the creation of longer lasting trains and cars, and a new form of transportation called Air-Ships!

The story follows Tatsu Frampt, a young boy who lives in an orphanage nowhere near the city, who dreams that one day he will be the captain of his own air-ship and travel around the world alongside his friends. He is told that he and his friends are being isolated from civilization due to a disease that makes iron grow in their bodies. However, the orphanage is attacked, and Tatsu is the sole survivor, and learns the dark truth of his "disease." Six years later, he embarks on a mission to save his friends, and kill those who stand in his way...