苍天的塞雷娜莉娅～何等美好的世界～

In a world powered by steam many advances have been made, even as far as steam-powered airships. Utilizing this technology, a militaristic empire has already taken over half of the continent. The story surrounds a freelance airship crew trying to make ends meet in this war-torn world.

When Connie, the captain of the ship decides to save a girl from the ruthless imperial soldiers (with the help of a mysterious boy), she stumbles into a journey that will take her ship and all its crew to the end of the world and beyond...

[First paragraph from a forum post by Asqualla]