A tragic disappearance. After a harrowing, otherworldly confrontation on the shores of Exmouth, Massachussetts, Special Agent A.X.L. Pendergast is missing, presumed dead. A shocking return. Sick with grief, Pendergast's ward, Constance, retreats to her chambers beneath the family mansion at 891 Riverside Drive--only to be taken captive by a shadowy figure from the past. An international manhunt. Proctor, Pendergast's longtime bodyguard, springs to action, chasing Constance's kidnapper through cities, across oceans, and into wastelands unknown. But in a world of black and white, nothing is as it seems. And by the time Proctor discovers the truth, a terrifying engine has stirred-and it may already be too late . . .