It's been two years since the vampiric virus was unleashed in The Strain and the entire world now lies on the brink of annihilation. There has been a mass extermination of humans orchestrated by the Master—an ancient vampire possessed of unparalleled powers. The future of humankind lies in the hands of a ragtag band of freedom fighters—Dr. Eph Goodweather, Dr. Nora Martinez, Vasiliy Fet, and Mr. Quinlan, the half-breed offspring of the Master who is bent on revenge. It's their job to overturn this devastating new world order. But good and evil are malleable terms now, and the Master is most skilled at preying on the weaknesses of humans.

Now, at this critical hour, there is evidence of a traitor in their midst, and only one man holds the answer to the Master's demise—but is he one who can be trusted with the fate of the world? And who among them will pay the ultimate sacrifice so that others may be saved?