In the final days of steam and airships, a mysterious woman is eliminating the world's great scientific minds using unrecognizable technology. A salvage diver from a notorious family is nearly killed when he discovers a scuttled Russian submarine fabricated from an unidentified black material. And a whiskey-soaked engineer narrowly survives an attack on Britain's most luxurious civilian airship.

Flying under the radar of military authority, the diver and engineer must follow the woman's electric trail of espionage into the wasteland of a parallel world, to prevent the destruction of their own.