The Wonder - Blood Red by James Devo

In some Worlds, Society depends on Technology to expand its horizons. In the Victorian world of the Wonder, Magic is the leading light. It powers an Empire through an Industrial Revolution towards boundless possibilities, including the invasion and colonisation of any neighbours who may have reserves of Magic themselves.
But the Wonder has been plumbed before, by past civilisations, and may have caused their collapse. Can a disparate group of accidental heroes made up of burnt-out dragoons, cynical mercenaries, a college professor and a nurse-cum-landlady from an Imperial backwater colony take on an entire Empire to save a world?