Arcadia is a world where continents float high above, and people travel by airships. Among the countries of this world, the most powerful one is the Empire of Valua. Guided by its greedy admirals, Valua strives to possess all the power in Arcadia. The boy Vyse and the girl Aika are members of the Blue Rogues - noble pirates who attack only Valuan war ships. During one of their confrontations with a battle ship, they encounter a girl named Fina, who is on an important mission whose secret she cannot tell yet. Involved in the conflict with the Empire of Valua, the trio of the heroes must explore the whole world of Arcadia in order to defeat the admirals.