Former New York City mayor Tom Cafferty has been haunted by the horror of that single day: the opening of the brand-new Z train subway line beneath the Hudson River, the supposed shining pinnacle of his tenure. But the ribbon-cutting ceremony turned deadly when the train carrying Cafferty's wife and other citizens was attacked by a horde of hyperintelligent, bloodthirsty creatures previously unknown to humanity. Everything changed for Cafferty, ex-NYPD officer Sarah Bowcut, and tech expert Diego Munoz that day. And they had uncovered another deadly truth: the attack was no accident. The creatures which wreaked havoc underneath New York have now spread worldwide, and facing a massive cover-up—and a secret organization holding whole nations hostage—Cafferty's team must fight against impossible odds to save the entire planet from an apocalyptic disaster.