God and Satan are at war in fount Royal and even the innocent are not safe. In the end, Matthew follows his head and his heart to unmask the true face of evil, and Rachel finds that her only escape leads halfway to oblivion and back.

The journey begins when Matthew, now an apprentice problem solver for the London-based Herrald Agency, accepts an unusual and hazardous commission. Together with his colleague, Hudson Greathouse, he agrees to escort the notorious mass murderer Tyranthus Slaughter from an asylum outside Philadelphia to the docks of New York. Along the way, Slaughter makes his captors a surprising--and extremely tempting--offer.