In an alternate England, where people who are wicked in thought or deed are marked by the Smoke that pours from their bodies, Thomas, Charlie, and Livia notice that some people appear to be able to lie without triggering Smoke. As they dig deeper, they discover teachers who have mysterious ties to warring political factions, a sumptuous estate which hides attic rooms and laboratories, revolutionaries who are fighting against a secret police force....

When Tudor explorers return from the New World, bringing along with them skraylings--magical beings--Mal Catlyn, a swordsman and bodyguard, uncovers the truth about the creatures and their powers, which could cost him his soul.