Cold Fire by Dustin Stevens is Book 1 of the 9 Jeremiah "Hawk" Tate Series. I didn't know this was considered Book 1 because I've read all of them so far but this one. Dustin made some editorial changes to this novel - but it isn't a story easily forgotten.
Hawk is readying the shutdown of his Montana Yellowstone/mountain guide outfit for the winter when a nice-looking woman stops by the office to hire him to help her find her brother who hasn't contacted her or her mother in several days. Supposedly from New Mexico, she won't take his standard refusal due to the encroaching weather conditions and keeps multiplying the zeroes on the price tag she's offering him. Although he hears the slight eastern-European accent in her voice, the money seals the deal. Gathering all the information he can about the man's last known whereabouts, he plots their course on his maps.
As they're hiking the considerable distance, the woman is relentless in pursuit furthering Hawk's suspicion that something isn't quite right. It isn't until they locate the man that Hawk finds out just how not right the entire trip has been.
When he finally makes his way back to his office, he knows where he needs to go and who he has to see. His old boss and friend, Hutch, still in his position in the DEA that Hawk left five years ago, listens as Hawk explains the totality of what happened in his bad adventure with the woman. A plan is launched, but nothing is working right. When Hawk teams up with his colleague Diaz, they're always one step behind. When they are forced to split up to solve this conundrum, Hawk heads for the head of the snake . . . in Russia.
A similar story in some ways to The Terminal List (Jack Carr), Hawk finally figures out who's at the top of all he's experienced.
There are some errors in places of this novel that better research would've made right, but the story is basically a good one.
Father, only you know the hearts of those you've gifted. Please help them to understand that apart from you, no one can do anything. In the Name of Jesus, Amen.