As a beautiful daughter of the noble family del Moral, Fana was proposed by Prince Carlo, who is the crown prince of their country Levamme. However, since Levamme is at war with Amatsuvian, the marriage had to wait until the war ends. Meanwhile, as a bestado, the lowest caste in Levamme, Charles had always dreamed of flying and eventually became the ace pilot of the air force. Although he was often mistreated, a glorious chance came about when the Amatsuvian bombarded del Moral's home in order to get rid of the future empress. Charles was then entrusted with the top secret mission of delivering the princess to the prince.
二国間戦争の真っ只中、名もなき飛空士・狩乃シャルルは類まれな操縦技術を見込まれ、次期皇妃ファナ・デル・モラルをその婚約者カルロ皇子のもとに送り届ける極秘任務を命じられた。護衛をつけず、水上偵察機一機で敵中を突破する危険な任務である。それでもファナを守り抜き、12,000kmを飛ぶべき理由がシャルルにはあった。次々に襲って来る敵空中艦隊と戦闘機を超絶テクニックで退けるシャルル。命をかけた空の旅の中で、ファナの閉ざされた心は開かれ、次第に二人は惹かれあっていく。やがて訪れた絶体絶命の危機の中、ファナのとった行動とは……。そして二人の恋の行方は……？
