Sierra Six

A TERRORIST BACK FROM THE DEAD. A DEBT TO BE PAID. Before he was the Gray Man, Court Gentry was Sierra Six, the junior member of a CIA action team. In their first mission they took out a terrorist leader, but at a terrible price - the life of a woman Court cared for. Years have passed and now The Gray Man is on a simple mission when he sees a ghost: the long-dead terrorist, but he's remarkably energetic for a dead man. A decade may have gone by but the Gray Man hasn't changed. He isn't one to leave a job unfinished or a blood debt unpaid. ------- 'I love the Gray Man'
Lee Child 'So propulsive, the murders so explosive, that flipping the pages feels like playing the ultimate videogame'
New York Times

Mark Greaney has a degree in international relations and political science. In his research for the Armored novels and the Gray Man novels, including The Chaos Agent, Burner, Sierra Six, Relentless, One Minute Out, Mission Critical, Agent in Place, Gunmetal Gray, Back Blast, Dead Eye, Ballistic, On Target, and The Gray Man, he traveled to more than thirty-five countries and trained alongside military and law enforcement in the use of firearms, battlefield medicine, and close-range combative tactics. With Marine Lt. Col. Rip Rawlings, he wrote the New York Times bestseller Red Metal. He is also the author of the New York Times bestsellers Tom Clancy Support and Defend, Tom Clancy Full Force and Effect, Tom Clancy Commander in Chief, and Tom Clancy True Faith and Allegiance. With Tom Clancy, he coauthored Locked On, Threat Vector, and Command Authority.