London, 1816. After many years confined to an asylum when her ability to sense the emotions of others drove her temporarily mad, Lydia Wescott, Extraordinary Discerner, now serves England as a secret agent. Recruited by the Duke of Craythorne to stop a threat to the King of England, Lydia travels to the American colonies, where intrigue and treason threaten on every side.

Lydia wants nothing more than to put her Discerner's talent to good use, but her hard-won control could be an illusion. As Lydia and Craythorne close in on the traitors, Lydia's talent may be the downfall not only of England's enemies, but of herself.