Andy Flint is an agent with the CIA.
Was and Is would be more accurate. We have two periods of time for Flint's activities and each section tells of a considerably different Flint than the one.
The first set take place in the early 90's (1993) and show a young, earnest and dedicated new agent for the CIA. As a blurb for the first adventure mentions, "His first month in the job and the Russians want him dead." Flint is in his early 20's, fresh out of the Farm and ready to prove himself. His assignment to the Moscow Station was a coup but he is well aware of the fact that it is up to him to keep proving he deserves the posting.
The second set takes place around 20 years later. Flint is no longer with the Agency and, according to his own description, not often sober. Flint explains his departure as being a product of the Soviet Union's demise and the rise of the Russian Federation and new, better relations with America, coupled with the abrupt change of focus after 9/11 on the Middle East. The Cold War was over. Communism was no longer a constant threat. Terrorists and religious extremists were the targets and the now old hat Russian experts were no longer needed and were a drain on resources.
Watching the two versions of Flint is interesting because the first wants to show others, and himself, that he has what it takes to survive in the field and get the job done while the second starts out his adventures in desperate need of money and a fervent desire to finally sober up. The younger is learning his skills by earning the scars while the elder is remembering his skills to keep from earning more.
Playing a major role in both periods of Flint's life is Vladimir 'Vladim' Martirossian, a Russian who was in the wrong place at the wrong time and chanced to meet Flint. That chance will repeat itself and a friendship will develop which will be beneficial, and dangerous, to both.