The Agent's Covert Affair (To Protect and Serve, Book 9) by Karen Anders
Private detective Emma St John doesn't care about military jurisdiction. Her sister is critically injured - and Emma's baby nephew, Matthew, has been abducted by a vicious drug lord. She is determined to navigate through lethal cartel country to rescue the baby, no matter what. But she's stuck with a mysterious NCIS special agent...and Derrick Gunn is proving to be the kind of determined, cool-headed help she can't shake.
Staying strictly mission-oriented keeps Derrick alive - and alone. But all bets are off as he and beautiful, independent Emma fight to stay steps ahead of their enemies. Her resourcefulness and courage ignite a desire he's willing to go through hell to keep. But love and survival are never guaranteed...