This had elements that I've seen in other stories: cops going undercover into BDSM clubs, realizing you know the person you're supposed to be there to extract, even police officers who enjoy being submissive.
I really liked that even though so many elements were familiar, the story still managed to feel fresh. I enjoyed both of the characters. I liked that their history together, and especially their reason for breaking up, made sense.
3.5 stars, rounded up