Jack Stevens is an agent with the CIA.
Not when we first meet him, though. At that time he is a charter boat captain trying very hard to not be involved in anything other than his daily excursions and just getting along. Soon, though, he will meet the lovely Amy Larkin and his life, and his career, will never be the same again. But at the first introduction we have, he is quite contentedly living aboard (don't tell anyone because he is really not supposed to be) his vessel, a 40' Morgan, and enjoying his life. If you ignore having to shepherd vacationing teachers who want something different in the tropics but mostly drink a bit too much and get a bit too nauseous on the deck.
Before this existence he had been working and living in the Big City at a finance job that he really did not like making a whole lot of money that he did like. He was married to Camille who he really like a lot until he didn't anymore and when she left she took most of everything he had even though she already out-earned him. Living then in a tiny place he really hated. The only thing he still had was his sailboat and some money he just got in a way the SEC would not approve of so he unfurled the canvas and headed south.
So it was that when our knowledge of him starts he is happy again, and single again, in a marina outside of Miami which is operated by his brother, Nat, a fellow fishing boat captain.
And that is when the beautiful Amy walked down the beach and into his life. Now it is important to note that to someone like Stevens, if a gorgeous woman like Amy stops by to chit-chat, you make friendly. When she comes back later and hands you an envelope with money in it to be available to help her should the situation arises, you sit up and pay attention because you know something interesting is bound to happen.
Which it does.