Judge by Elle James

Former Delta Force Operative Joe “Judge” Smith came to work at the Lucky Lady Lodge to help rebuild the old girl to her former glory. Tired of killing, he wants to shoot a nail gun, not a military-grade rifle. Since arriving at the lodge in Montana, he and his team have been embroiled in one dangerous mission after another, unable to avoid using their combat training to help people defend themselves against a radical organization, The Chosen Way. Determined to locate their latest compound and find their leader, Judge goes undercover to infiltrate and gather the intelligence needed to bring them down.
The Chosen Way’s assassin, PJ, is tasked to train Judge, their newest recruit. Like many members of the organization, she was coerced into submission to protect her family and friends. Saddled with a new recruit, she’s surprised at his skills and physical abilities and more than a little attracted. When Judge escapes with another recruit, PJ is given 48 hours to eliminate Judge and bring back proof that he is dead, or she and everyone she loves will be killed. With the clock ticking, PJ can’t bring herself to murder Judge, a man she’s falling in love with. Together, they devise a plan to take down the TCW’s radical leader and dismantle the group forever. Only then can they give in to their growing passion.