Blake Barrett is a freelance agent.
Sort of. We watch him on a mission for MI6, highly unusual since Barrett is American, at the beginning of the first recorded adventure, hired by them to break into a high security Russian facility, obtain a top-secret thumb drive, and get back out without killing anyone. We are given the impression that this is not his first mission for the UK intelligence agency and there would likely be more to come if it hadn't been for a very fateful fishing trip.
Barrett honed his impressive skills serving in the U.S. Air Force as a Special Reconnaissance Airman. He had all that was needed to be a top-tier operative except for one thing, pretty much summed up by his best friend thinking back to those days they served together in Afghanistan. "There's no question you were one helluva operator when it came to breaking into a highly-guarded facility and stealing secure intel from a protected server. Your shooting skills were also tops in our class. And you had nerves of steel, unwilling to let any situation rattle you, no matter how dire it got. You were also very creative, adept at figuring out how to solve impossible situations. But there's one thing you just couldn't do, one thing you didn't have the stomach for."
That was killing. Barrett knew how to and he also knew that if he truly had to, he could. The problem as his friend, and his superiors back in the military in those days saw it, Barrett would more likely find something good enough in a potential target to let the man walk. Since, it turns out, he and his best friend, Gordon, were being scouted for a very clandestine but impressive position, that mercy was an undesirable trait.
So Barrett saw his career in the Air Force take a nosedive and he looked for work elsewhere, hence the temp assignment for MI6. They liked him because "He specialized in discretion".
Now, back to that fishing trip. His pal Gordon suggested it. They reunited in the Ozarks and went out on a large lake there to drink a couple of beers, catch a lot of wide-mouth bass, and shoot the breeze. Then Gordon tried to kill him and discovered that Barrett, for all his merciful ways, can still kill when needed.
The question that Barrett has, obviously, and the one driving the adventure onward, is ... why?