As the McClane saga continues, the family realizes that someone in their trusted, inner circle may just be the person who has leaked precious information about them, Fort Knox, and their community allies to the men who were running the highwaymen and ultimately to whoever they were reporting. It becomes a quest for vengeance, a vengeance of the innocent people murdered for months on end by the highwaymen. Will time run out before they can stop the damage being done to their family and allies or will they sniff out the traitors in time to finally end it?
And while the manhunt continues, Simon, who has finally reconciled his feelings for Sam, must find a way to win her over after the pain he has caused her fragile heart for rejecting her. However, it proves more difficult than he anticipates as she has made a promise to herself to close Simon out of her life forever. Little does she know, Simon has finally come into his own and is up for the challenge.
When the story concludes, the McClane family will be put to the biggest test of their lives since the fall and are faced with drastic changes to their family dynamic when General McClane calls them to a meeting at Fort Knox to discuss their fates. And all Herb wants to do is hold his family together, keep them safe, and protect them. But at what cost will that come?