Body exchange proves fatal in a love triangle while a mission to alter history runs amuck.

Coin has lost everything. Ten years ago, his father vanished into the Austrian countryside. Six months ago, his entire family save two cousins fell victim to the Weeping Death as it swept its way across Scotland. Now, he’s lost his own life and the lives of his cousins to a bad choice. But if he can navigate Joseph Paxton’s great labyrinth of illusions, he might at least redeem his cousins’ lives.

Helen has everything to gain if she can stave off marriage and maintain her position as Joseph Paxton’s protégé by showing herself a worthy aide to his many technological endeavours. But Paxton has set his intensions on Coinneach Throckmorton, declaring him the answer to the challenge the Dukes of Devonshire and Wellington now face. If this condemned miscreant solves the labyrinth before him, he’ll likely supplant Helen at Paxton’s side. But if Helen doesn’t do all she can to help Throckmorton through the challenge, his two cousins, one a lass who should still be in leading strings, will share his fate of prison or worse.

With France overwhelming Britain in every corner of the globe, Devonshire and Wellington have plans to slip into the past and abscond with the great illusory technology of Ludibrium, a preternatural substance of unparalleled military, communication, and entertainment capabilities. Only the great inventions of Britain’s best minds have prevented France from taking London itself. Since a message from the future arrived at the gates of Devonshire House, Joseph Paxton has been obsessed with duplicating the machine that made the delivery. Now he’s sure Throckmorton holds the key to success.

Misadventure strikes when an experiment goes wrong and Helen and Coin exchange bodies.