San Francisco is infested. Crime stains the streets, and the SFPD battles to keep it under control. Among the department’s finest, Detective Patricia Ryder marches to her own drum, solving cases through a combination of balls and brains. But a case comes across Ryder’s desk that leaves even the brazen detective at a loss. Multiple victims ranging in ages and backgrounds have all been found beheaded, apparently without connecting motive. From children to pensioners, the results remain the same. What kind of callous beast could perform such atrocious acts? And then she meets him. The killer mouths a tale so incredible that Ryder is forced to laugh it off. But then he proves himself by doing the impossible. Torn between her need for facts and her inability to deny what she sees with her own eyes, Ryder teams up with a man she believes is a sociopath in order to thwart a being of colossal power, something so ancient it makes Earth seem like a newborn. It is hungry. It is relentless. It has its sights set on our world. And only a cop and a killer stand in its way.