Dr. Rhea Lynch and the E.R. team are about to face a gruesome and mysterious virus that kills within hours of being contracted. As people are rushed into the E.R. and illness claims more lives by the hour, Rhea begins to draw some conclusions about the nature of the virus...and its connection to the military. But even as she begins to put the pieces together, Rhea fears that she has discovered something far more dangerous than she'd ever imagined -- and can only pray that she's not too late.