Anthony Cade / Prince Nicholas Obolovitch
An English-educated adventurer who undertakes Jimmy's errands, investigates the crimes, and conceals his own royal identity.
Virginia Revel
A witty young widow whose shared name with the letter writer draws her into the blackmail plot; she becomes Anthony's partner and wife.
Superintendent Battle
The Scotland Yard detective whose understated questioning and patient suspicion guide the official investigation.
Lord Caterham
The owner of Chimneys, chiefly concerned with avoiding guests, politicians, and further national crises.
Lady Eileen 'Bundle' Brent
Lord Caterham's energetic daughter, a quick observer and famously fearless driver.
George Lomax
A self-important government official managing the diplomatic and financial consequences of the Herzoslovakian restoration.
Bill Eversleigh
George's assistant and Virginia's persistent but unsuccessful suitor.
Hiram Fish
An American presented as a rare-book collector but actually working for Pinkerton's to capture King Victor.
Monsieur Lemoine / King Victor
The apparent French detective is an impostor; he is the celebrated jewel thief using official authority as cover.
The real Monsieur Lemoine
The Sûreté detective kidnapped and held at the Dover headquarters before Anthony and Fish rescue him.
Mademoiselle Brun / Queen Varaga
The false governess, Anthony's presumed-dead stepmother, King Victor's accomplice, and Prince Michael's killer.
Prince Michael Obolovitch
The royal candidate murdered after recognizing Queen Varaga at Chimneys.
Boris Anchoukoff
Prince Michael's devoted servant, who instinctively transfers his loyalty to Anthony and helps defeat Varaga.
Jimmy McGrath
Anthony's Canadian friend, whose two commissions set the entire plot in motion.
Herman Isaacstein
The financier prepared to back a restored Herzoslovakian monarchy in exchange for oil concessions.
Baron Lolopretjzyl
A loyal Herzoslovakian royalist seeking a legitimate heir.