Awaken Me Darkly - Gena Showalter
One of the great virtues of getting books off the internet (for me, at least) is when you want to pick up a book like this but don't want someone in a library to look at you when you're doing so...

Where Awaken Me Darkly is concerned, as with some other books, part of the problem is the cover with the half-clothed buxom woman, particularly when it doesn't really bear all that much resemblance to what actually goes on in the pages. In the case of this book, given that our protagonist is an alien hunter who delights in kicking the arses of people much bigger than her, it only reflects a part of the book and not its whole.

Anyway, Mia Snow is in the business of hunting and killing aliens, which is all perfectly legal and above board if those aliens have broken the law. She's part of a team that do this for a living, but when her partner is seriously injured the only one who can apparently save him is a mysterious alien, who is prepared to lend a hand if Mia will allow herself to become involved with him. It's not too difficult to figure out what happens next... the series continues (kind of) in Enslave Me Sweetly, which is set in the same universe.