An adaptation based on Keiichi Sigsawa's series of 3 light novels. Set in a world comprising a single continent split by the Lutoni River and Central Mountains into two warring nations, Roxche and Sou Beil, the narrative follows Roxche pilot Allison and her childhood friend Wilhelm. They embark on a perilous quest for a legendary treasure located in Sou Beil territory, which may bring an end to the conflict between the two countries.