Castle in the Stars Vol. 3: The Knights of Mars
What if humanity journeyed into space in 1869, not 1969? Upon returning home from their perilous voyage to the moon, Seraphin and the Knights of Ether make a bold choice: To keep their aethership out of the hands of the Prussians, they must reveal the secret of space travel to the world. Afterwards they seek refuge on a quaint island in Brittany, but their journey is long from over. The villainous Prussians have discovered their hiding spot, and they'll stop at nothing to commandeer their ship. An explosive chase ensues, leading our heroes all the way to the uncharted terrain of Mars!