Operation Phoenix — Susan Hayes

He's guarding the galaxy. She's guarding her heart.
Commander Dax Rossi lives by one rule: mission first. But when an old flame puts that code to the test, he needs to make a hard choice--the job, or the woman?
Lieutenant Trinity West wants answers. Someone's been stealing DNA from her top-secret research base, and she wants to know who, and how. Her investigation into the thefts is cut short by the arrival the only man to ever break her heart -- and now he stands in the way of her discovering the truth.