The monastery's abbot asks them to recover a stolen relic, the cryptic Agozyen, which could, in the wrong hands, wipe out humanity. The pair follow the trail to a luxury cruise ship, where a series of brutal murders suggests the relic's evil spirit might already have been invoked.
Fans of earlier books focused on a thinly disguised American Museum of Natural History may find less at stake among the new cast of secondary characters, but the fate of Constance, who claims to have aborted the child of Pendergast's villainous younger brother, remains a potent subplot.