Secret Service agent Jo Harper returns to her hometown of Black Falls, Vermont, to hide out in until she can assess the damage to her career. On her watch, Jo fell for a prank perpetrated by the vice president's 16-year-old son and his friends. After the boys posted a video on the Internet, her anonymity is blown. Jo arrives home to discover her ex- lover, Elijah Cameron, recovering from his father's unexpected death and from grievous injuries received in combat.

Their tentative reunion is cut short by the suspicious death of an ambassador in Washington D.C. and the disappearance of his stepdaughter, Nora, in the Black Falls Mountains. Jo and Elijah put their conflicted feelings aside to search for Nora. Working with family, friends and associates, Jo and Elijah uncover a network of killers assassinating seemingly unrelated targets. The killers systematically remove anyone who poses a threat to them. Some unexplained deaths now make sense. Running against time, Jo and Elijah tackle the mountain during a major snowstorm, trying to find Nora before the killers do.