Forced to abandon aviation school, Haruki ends up in a dead-end job, his dream of flying stolen. However, on his days off, he escapes to the countryside to work on the Kenichi Modern: his very own biplane.

But on the day of its maiden flight, Haruki falls into the sky—and crashes into another world, alongside his plane.

In that world, elves are real, and magic dominates the land. There, he meets the young elf Anemone who shares his dream to fly high in the sky—in a land where flight is but a fantasy. Finding every reason to share his dream, he takes her on a romantic first flight.

But their joy is short-lived. From the Inverted Tokyo hanging in the sky descends the Sky Legion: a malevolent force that threatens the land. And within that city, Haruki glimpses the impossible—a path home.

Together with Anemone, they must battle the Sky Legion with magic and machine as one. Will he survive long enough to return home, or will the world in the sky claim him as its own?