Will Robie and Jessica Reel are two of the most lethal people alive. They're the ones the U.S. government calls in when the utmost secrecy is required to take out those who plot violence and mass destruction against our nation. And through every mission, one man has always had their backs: their handler, code-named Blue Man.

But now, Blue Man is missing.

Last seen in rural Colorado, Blue Man had taken a rare vacation to go fly fishing in his hometown when he...