A mercenary and a princess thrown together in a war that neither of them started discover they're the only two people who actually believe love matters. The animation during their flight across enemy skies looks like nothing else, clouds and horizon rendered with such care that you feel the weight of every stolen moment between them. By the end, you're not rooting for them to survive the war. You're rooting for them to have one more day together.

Juana del Moral, daughter of a noble family, receives a proposal from the crown prince of the Levamme Empire, who vows to end the long war with the Amatsukami Imperium within a year so they can marry. When the Amatsukami bomb the del Moral home to eliminate the future empress, the San Maltilia air force turns to Charles, its ace pilot. He is a bestado, a man of mixed blood from the lowest caste, who has long been mistreated despite his skill. His top secret mission is to fly Juana alone across an ocean and through enemy territory to reach the prince in the Levamme capital, a journey far more perilous than anyone expected. The film adapts a light novel by Inumura Koroku.