The show moves like a 1930s adventure serial that actually believes optimism is earned, not given. Each three-episode arc lets you fall in love with a new corner of the world, then pulls you out before the weight sets in. Allison and Lillia inherit a mission from their parents that never stops mattering, even when the show treats catastrophe like a plot beat instead of the end of the world.

Two nations split by a river and a mountain range have fought for more than a century and now hold an uneasy ceasefire. Allison, a pilot in the Roxche air force, reunites with Wil, a friend from the orphanage where they grew up. Together they are drawn into an adventure in enemy territory, searching for a legendary treasure said to be able to end the war. About fifteen years later, their daughter Lillia carries on their hope of a united continent. Her own adventure begins during a summer break from school, alongside her childhood friend Treize.