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.

Before he was considered a CIA superagent, before he was thought of as a terrorist's worst nightmare, and before he was both loathed and admired by the politicians on Capitol Hill, Mitch Rapp was a gifted college athlete without a care in the world...and then tragedy struck.

Warning: The next terrorist attack on American soil is coming...sooner than you think. They can strike anytime, anywhere. A public landmark. A suburban shopping mall. And now, the human body itself. Three Middle Eastern terrorists have been injected with a biological weapon, human time bombs unleashed on American soil. They are prepared to die. To spread their disease. To annihilate millions. If America hopes to fight this enemy from within, we need a new kind of weapon. Meet Special Agent Jericho Quinn. Air Force veteran. Champion boxer. Trained assassin.

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.

On his last combat deployment, Lt. Cmdr. James Reece's entire team was killed in an ambush that also claimed the lives of the aircrew sent in to rescue them. But when those dearest to him are murdered on the day of his homecoming, Reece discovers that this was not an act of war by a foreign enemy but a conspiracy that runs to the highest levels of government. Now, with no family and free from the military's command structure, Reece applies the lessons that he's learned in over a decade of constant warfare toward revenge.