Three top secret research scientists are presumed dead in a boating accident, but the kidnapping of their families the same day raises questions the FBI and local police can't answer, leaving them waiting for a ransom demand that will never come. Central Intelligence Agency analyst Chris Leroux stumbles upon the story, and finds a phone conversation that was never supposed to happen. When he reports it to his boss, the national clandestine services chief, he is uncharacteristically reprimanded for conducting an unauthorized investigation and told to leave it to the FBI.

A violent encounter forces Kane to emerge from a life in hiding, where he had hoped his wife and children would be safe. He must go on the run and fight for the lives of those he holds most dear. The forces out to kill him are skilled, well-armed, and his former colleagues in the Mjolnir Agency, a black-ops shadow section of MI6.

In a desperate attempt to prove his innocence, Kaine is forced to rely on two women he barely knows-a country veterinarian who treats his wounds and an IT expert with a dark secret of her own. Kaine must battle his overwhelming guilt, life-threatening injuries and strong moral code as he hunts for the people who turned him into a mass-murderer.

Court Gentry is known as The Gray Man—a legend in the covert realm, moving silently from job to job, accomplishing the impossible, and then fading away. And he always hits his target. But there are forces more lethal than Gentry in the world. And in their eyes, Gentry has just outlived his usefulness. Now, he is going to prove that for him, there's no gray area between killing for a living-and killing to stay alive.

As a lethal militia targets the most powerful man in the world, Jake must thwart their assassination plot and protect the nation's highest office—even if the mastermind behind it is a shadow from his own past.