Six, a highly-skilled assassin in the deep-cover Sierra program of the CIA, is the agency's best merchant of death. However, a mission goes bad and now Six is on the run from the CIA with ...

It is the latest in the Gray Man series. Author Mark Greaney joins us now. Hey, Mark. MARK GREANEY: Hey, how you doing? LIMBONG: Not bad. Not bad. All right, so set us up here a bit. This is the ...