Where Fire Meets Flame by Elena Kincaid

As a private detective, Riley Scott has witnessed her fair share of the ugly side of relationships. She guards her heart like a fortress, but a pair of sizzling blue eyes threatens to take down all of her barriers. He came to her rescue through a blazing fire. Now, she could only hope he would not incinerate her heart.
Tristan Cain hasn’t been able to let go of his red-headed angel, or his promise to get justice. Fate throws them together again when he once thought it would be impossible, and when a daring rescue turns out to be the least of their worries, Tristan vows to keep her safe. He’s not letting Riley out of his sight again.