Kurt Vetter is an analyst for the CIA.
He is definitely not a field agent and he would be the first to tell you that. He could have been, considering the physical condition he keeps himself and the innate skills he shows when life forces him into situations he would not willingly seek. But he is not trained as an operative and, until the first adventure in this series, he was quite happy not being one. Besides, as he tells himself more than once, an agent needed to be quick on his feet, able to access the situation and change at a moment's notice. That was not Kurt Vetter's strong point.
He left that to his brother, Mike. Mike was an experienced agent, working for the Agency for quite a few years in places he never talked about doing things he sometimes wanted to forget. Mike was very good at his job, good enough that he could head to remote locations and risk his life for his country and then come home again to a wife and kids.
Kurt, however, was with a family. He had had one but an ambulance racing to help others accidentally took the lives of his wife and daughter, leaving Vetter with painful memories and a wish to just get away. It was "away" in Peru trying to find himself that he got word of his older brother's death.
One tragedy ripped Vetter from his comfortable, desirable life. Another tragedy pushed him back into reality and would change his life forever. The elder Vetter had been a star at the CIA, something Kurt had not sought. He had also been involved in something he would come to regret and that would get him killed. It would also move his younger brother into a whole new world.
In this new world was Amanda Carter. Once a colleague of the older brother, her relationship with the deceased Vetter was something she preferred to not talk about. That she had been an agent, though, was obvious from the moment they met. Her take one Kurt was not very positive and his of her was also lacking in warmth but the two would find working together the only way to stay living.