An adaptation based on the series of 3 light novels by Keiichi Sigsawa. Set in a world of a single continent divided by the Lutoni River and Central Mountains into 2 warring countries, Roxche and Sou Beil, the story follows Roxche pilot Allison and her childhood friend Wilhelm in their dangerous quest for a fabled treasure in Sou Beil territory that may end the war between the 2 nations.