Four months after the deadliest attack on the American homeland since 9/11, terrorists leave a trail of carnage through London's glittering West End. The attack is a brilliant feat of planning and secrecy, but it has one loose thread: the French Moroccan street criminal and ISIS operative who supplied the combat assault rifles. The thread leads legendary spy, assassin, and art restorer Gabriel Allon and his team to the south of France and the gilded doorstep of Jean-Luc Martel and Olivia Watson. A beautiful former fashion model, Olivia pretends not to know that the true source of Martel's enormous wealth is drugs. And Martel, likewise, turns a blind eye to the fact that he is doing business with a man whose objective is the very destruction of the West. Together, under Gabriel's skilled hand, they become an unlikely pair of heroes in the global war on terror.