One ordinary afternoon, research specialist Dr. Erin Cross steps into a local deli to get some lunch, and nearly takes a bullet instead. Thanks to the timely intervention of a former Marine, she walks away from the seemingly freak incident. But when she returns to find her lab under security lockdown and her apartment ransacked, she realized the attack was anything but random. Erin can’t make sense of the threat, given her low profile after a disastrous H1N1 vaccine trial. She doesn’t know her former colleague has used the virus to develop a potent bioweapon or that her recent research hold a key to his success. And she doesn’t know that his collaborators want her dead before she blows the whistle. Fleeing for safety with her research in hand, Erin unravels the threats with the help of the timely Marine, former Special Ops agent Sean Flannery. But the closer they come to finding answers, the more questionable Sean’s behavior becomes. His erratic moods and suspicious communications are more fitting for an enemy than a friend. And as the crisis comes to a head, Erin can’t be sure who harbors more secrets—the bioterrorists pursuing her or the one man who can give her protection.