Mission Critical by Mark Greaney

On a midnight flight from London to Washington, Court Gentry — the Gray Man — is pulled from the shadows and thrust into a mission he never expected. His task: protect a high-value CIA asset being transported for interrogation. But when the plane is attacked before it lands, the operation shatters — and Gentry becomes the target.

Half a world away, a rogue assassin is on the same trail, guided by motives buried deep within the intelligence community. As global powers close in and alliances fracture, the Gray Man races to uncover a conspiracy that reaches the highest levels of espionage.

Every move he makes brings him closer to the truth — and closer to a betrayal that could change the balance of power forever.