Hot on the Hunt (Harlequin Romantic Suspense Series #1809)

This ex-agent has one last chance to mend a broken relationship—if he can protect her long enough 

Burned black-ops agent Alicia Troy spent years plotting the perfect revenge on the man who left her for dead…until her plan is foiled by her ex-teammate—and ex-lover—who taught her the meaning of betrayal. She can't trust John Witter…so why can't she stop wanting him? 

For John, it's a race to keep Alicia's intended victim safe long enough for the man to prove John's innocence, and it's a struggle to steer clear of the woman who believes he deceived her. But when their former agency turns on them, labeling them "armed and dangerous," John has a new mission: keep his woman alive.