A mysterious alien object attacks a Naval ship and crew. Dr. Molly Anne Caffrey, a government contingency analyst, is contacted by the Deputy National Security Advisor, J.T. Baylock, to investigate the incident along with a special scientific team of her choice.

Molly and Baylock realize the Threshold detainees must be moved immediately to a more secure facility in West Virginia when a prisoner attacks and infects a security guard, then tries to break himself and other infected prisoners out of their cells.

Lucas is infected with the alien DNA from something he ate. The infectees have harvested crops with the alien DNA. Caffrey must find a way to stop what could be nearly 200 new infectees. Also, one of the aliens approaches her with an interesting revelation.

When a number of infectees and seemingly innocent people are killed, it becomes apparent that someone is going after people affected by the alien signal, and is locating them via their heightened brain waves. How is the killer linked to Bighorn crewman Manning, and does his method of finding his victims mean that Molly, Cavennaugh or Lucas could be next on his list?