Chance Hughes is an assassin for the CIA.
When we first meet him, he is a prisoner of the Taliban in the mountains of Afghanistan, drugged and tortured on a daily basis by a rag-tag group of Al Qaeda wannabees and certain he had been given up for dead. After being a 'guest' of the terrorist cell for over half a year, he was rescued by Navy Seals who brought him back to safety and another opportunity to serve his country.
The second of two sons of a former Marine who went on to become a Senator from a Mid-West state, Hughes was 13 when his parents were killed in a terrorist attack. He was raised by his older brother, James, until he reached 18 and joined the Marines. His desire to do something to stop the mentality that took two-thirds of his family was too strong to let him consider anything else and while he knew he would not be able to get the actual people responsible for their deaths, he could at least work to stop other kids losing their parents.
One thing that Hughes did not know was that he was being studied by a group created by a former CIA Special Operations Division chief who saw a need for an organization which could operate outside the bureaucracy of Washington. He put together the team to make up what he called the Off-Grid Operations, or OGO, and found the funding for it. Numerous people chosen to be a part of this off-the-books group gave it an impressive level of sophistication and expertise but one thing badly needed was an operative to take care of business in the field. Someone like Hughes.
An expert with languages, a sniper with exceptional skills, and a man whose operational awareness bordered on the spooky, Hughes was a perfect candidate to be asked to join. Then, of course, he got captured on a mission that went horribly wrong and though he had been the key instrument in saving many of his team-mates, he paid the price with the torture he endured for many months.
Now back State-side, Hughes is offered that chance to join and he agrees. Gunnery Sergeant Hughes will be assisted in his work by his brother James, a computer whiz, and will work directly under CIA case officer Gabrielle O'Connor, herself also secretly a member of OGO, as he takes his style of war to the enemy.