This is book number 6 in the Ghostwalker Novels series.
Saber Wynter is running from her past when she meets Jess Calhoun, an ex-Navy SEAL who is physically and emotionally compromised by his own mysterious and violent history as a GhostWalker. What Jess senses in Saber is a kindred spirit, a lost soul desperate for sanctuary. He offers her a home, a job, and a haven where she can safely reveal the secrets that shadow her. But danger follows her, too. Now, the riddles of both their pasts are about to collide, shattering the promise of their future with the ultimate betrayal.