Olivia Santos is an agent with the CIA.
Trent Mann is an operative with Potomac Private Services (PPS).
A bit more on that company reveals that it was created by a close friend to Mann, Jake West, who had started it "for men and women like him-people who had seen the darkest side of humanity and come out intact. Well, mostly intact. Former special forces operators, undercover law enforcement agents, and intelligence specialists tended to trust their guts. Sometimes a person knew they were in the soup before they knew it. Call it instinct, call it a hunch, call it what you will, Jake respected that feeling." PPS will play an important role in all of the adventures we follow Santos and Mann, and several others, on.
Back on Santos, we learn at the very beginning of the recorded adventures that she "lives on a razor's edge. As a NOC-an agent with non-official cover-she's well aware of the risks: if her cover's blown, there's no diplomatic immunity, and a life sentence in a foreign prison is the best-case scenario. The worst-case scenario is too gruesome to mention." We also find that she is locked in a marriage with a controlling man who uses his power and wealth ("more money than Midas") to try to keep her in line - it is not working but it is proving very annoying to her. Described as "a fiery blonde with the enormous eyes", her beauty is enough to attract a lot of attention, something she has to work to prevent.
As for Mann, he once "thrived on danger" but now, "haunted by a costly mistake in his past, he focuses on his work for PPS to hold his nightmares at bay". Since he has chosen to keep himself out of the field for now, the memories of "the jihadist ambush and execution" of someone close to him still too strong, he is part of the training staff at PPS's facility along the border between the two Virginias. It is as an evasive driving instructor there that he will come into contact with Santos. Prior to his employment with PPS, Mann was a "Black Squadron sniper/recon/intel/surveillance operator", or as he thought of himself, "a simple SEAL Team 6 guy".
As the series progresses, other people will take center stage although Santos and Mann will continue to play major parts in each of the ensuing adventures. After three tales about Santos and Mann, it will be Mann's employer, Jake West who will be the focus along with a professional outdoorswoman and outfitter, Chelsea Bishop, Santos' cousin and close friend for three more adventures. That will lead to Ryan Hayes, an attorney for PPS, and Leilah Khan, a professional racecar driver, who find themselves in considerable danger. As mentioned, Santos and Mann will not be far from the action.