Ex-military investigator Jack Reacher returns to his old headquarters to meet Major Susan Turner, the new commanding officer of his old unit, with whom he's been working closely via phone to solve cases of military corruption. Upon arrival, he discovers that Turner has been arrested on charges of espionage. Reacher quickly becomes embroiled in the conspiracy and realizes that Turner may have been set up. He decides to look into the case himself, but not before learning he may have a personal connection he never anticipated—a potential teenage daughter from a past relationship, adding an unforeseen personal stake in the events unfolding.

As Reacher delves deeper into the conspiracy to clear Turner's name, they both escape custody. Together, they uncover a private military contractor's involvement in illegal arms sales, facilitated by members within the military. With the contractors and the military police hot on their tails, the pair must race against time to find the truth. Their journey to uncover the corruption leads them to New Orleans, where they must confront the contractor’s head and his team of mercenaries while trying to protect each other and Reacher's alleged daughter from the increasing danger that threatens to end their mission and their lives.