In the floating-island world of Cloudia, cavalry platoon leader Reinas of the Kaisershult Empire is sent to conquer Badelsen Island alongside his ally Ronald. The mission succeeds — but Reinas refuses to participate in the massacre of civilians that follows and is immediately at odds with Ronald. Convicted of treason, he is cast out of the Kaisershult army and would have died without the intervention of Bernheim and Nia, who pull him to safety and offer passage on their airship. Traveling to the magical kingdom of St. Mira, Reinas meets Hunt and Vice, repels a Kaisershult invasion of the kingdom, and earns an audience with the king. There he hears troubling rumors: the King of Kaisershult has been behaving suspiciously, and an Airgate exists somewhere in the world — a passage whose nature nobody has fully explained. Reinas and his companions head for the tower of the god Ptelux, said to be sealing it.