Someone calling himself Matthew Hopkins—the name of the 17th-century Witchfinder General—is killing people he deems modern-day witches.
But first he calls DS Grace O’Malley on her mobile phone to warn her of impending trouble, and signs off by saying, "I know where Dominic is!" Dominic Boswell is Grace’s husband, the assistant commissioner of London’s Metropolitan Police, and she finds him handcuffed to a bed about to have sex with a prostitute. Determined to divorce him, Grace leaves Dominic there and gets a call about a woman burned to death on a boat floating down the Thames. By now, BBC reporter Juliette Bouchet has also had a call from Hopkins, who directs her and a cameraman to Westminster Bridge ten minutes before midnight on Halloween. The area is crowded with costumed revelers, including a bunch of Oxford students carrying Count Dracula in a coffin, who all get to see the fiery boat with its human cargo, medium Veronica Crosse, explode as it passes under the bridge. A police team explores all aspects of the well-planned crime, which required technical expertise and several people, one of whom may have had inside knowledge. The pressure to solve the mystery is intense even before medium Abigail King is killed in another show by the Witchfinder, and a simple but devout preacher who believes in witches becomes part of the picture. When a fork is found in Crosse’s mouth with the prime minister’s fingerprint, all hell breaks loose. Investigations reveal even more high-up involvement, but Grace refuses to back down from a complex, dangerous investigation made more difficult by hints and threats from the Witchfinder.
Enriched by historical data, this spellbinding police procedural has a vicious sting in its tail.