In the midst of a brutally cold winter in Pittsburgh, Daniel Rinaldi is asked to treat Lyle Barnes, a retired FBI profiler whose terrifying nocturnal visions cause him to wake up screaming. Barnes, after twenty years spent inside the minds of the nation's worst serial killers, is not only falling apart psychologically but also finds himself the target of an unknown assassin, whose mounting list of victims is paralyzing the city. Hidden for his own protection by his former bureau colleagues, Barnes secretly escapes, drawing Daniel and a joint task force of the FBI and the Pittsburgh Police Department into a desperate manhunt. They must try to find the missing agent before the killer does.