For Gabriel and his wife, Chiara, it was supposed to be the start of a pleasant weekend in London—a visit to a gallery in St. James’s to authenticate a newly discovered painting by Titian, followed by a quiet lunch. But a pair of deadly bombings in Paris and Copenhagen has already marred this autumn day. And while walking toward Covent Garden, Gabriel notices a man he believes is about to carry out a third attack. Before Gabriel can draw his weapon, he is knocked to the pavement and can only watch as the nightmare unfolds.

Haunted by his failure to stop the massacre, Gabriel returns to his cottage in Cornwall, until a summons brings him to Washington, into a confrontation with the new face of global terror. At the center of the threat is an American-born cleric in Yemen to whom Allah has granted “a beautiful and seductive tongue.” A gifted deceiver, once a paid CIA asset, the mastermind is plotting a new wave of attacks . . .