Someone screwed the timeline up
It's 2150, and the Earth's starting to get over the Great Apocalypse of 1906. From the steampunk sky-cities of Isla Aether and High Tortuga, airship pirates ply the clouds, in search of excitement and booty, kept in check only by the might of the Imperial Air Navy.
Down below, North America is a wilderness, its beast-haunted wastelands criss-crossed by the tracks of the freedom-loving Neobedouins and the armoured railroads that connect the Emperor's widely scattered domains.
In the walled, smog-shrouded cities, people huddle in forced Victorian squalor, lorded over by the upper classes, while the Emperor's clockwork policemen patrol the streets and the ultimate threat of the Change Cage hangs over those who would rebel.
You've got yourself an airship. You've got yourself a crew. You've got yourself one of Doctor Calgori's fancy chronominautilus devices. All you need now is a good swig of rum (trust us, you'll need it), and you're ready to set sail on the winds of time and plunder history itself!
Who knows, maybe you can screw up the timeline some more?