Asked to advise on the antiques collection of a mysterious widow, Arnold Landon enlists the aid of an old friend, Carmela Cacciatore of the Carabinieri Art Squad. He soon finds himself drawn into the investigation of an antiquities smuggling operation which leads to murder in La Rochelle, the involvement of the CIA and the hunt for an ancient religious manuscript looted from the Baghdad Museum after the fall of Saddam Hussein. And lurking in the background is the threatening figure of an assassin trained by SAVAK, the murderous secret service established by the Shah of Iran, the Peacock Prince. But it is in Northumberland that Arnold finally learns the truth and faces the deadly menace of the Shadowmaker.