In a Victorian era ruled by a council of ruthless steam barons, mechanical power is the real monarch and sorcery the demon enemy of the Empire. Nevertheless, the most coveted weapon is magic that can run machines - something Evelina has secretly mastered. But rather than making her fortune, her special talents could mean death or an eternity as a guest of Her Majesty's secret laboratories. What's a polite young lady to do but mind her manners and pray she's never found out?

But then there's that murder. As Sherlock Holmes's niece, Evelina should be able to find the answers, but she has a lot to learn. And the first decision she has to make is whether to trust the handsome, clever rake who makes her breath come faster, or the dashing trick rider who would dare anything for her if she would only just ask.