March, 1917. The goal of every government involved in the Great War has been achieved: industrialist Spenser Cochran has drugged and enslaved a vampire, Don Simon Ysidro, to do his bidding, and is now on the way to the US aboard a luxury ship.

Horrified, Dr Lydia Asher secures her passage on the vessel to rescue her friend from Cochran's chemical thrall. Meanwhile, her husband makes a dangerous alliance with the vampires of Paris to send Lydia the information she needs about the drug.

As they cross the Atlantic evidence mounts that another vampire is hiding aboard the ship, indiscriminately murdering passengers. Lydia knows she must solve both cases before the ship docks, and that breaking Cochran's hold on Don Simon will not be enough . . . She must kill him.