Mercury's War by Lora Leigh

The Breeds are a genetically engineered cross between humans and animals, meant to be soldiers, spies and slaves to humanity. Most of them lived lives of danger and brutality in the labs where they were grown and born, but over 20 years ago, they rebelled and seized their freedom to live and exist as all humans do. Now, though the ones who created them agitate for returning them to the labs as soulless animals, the Breeds must still defend themselves and protect their interests from the people who would enslave them again.

The Breed have set up a place where they can defend themselves, called Sanctuary, and employ both Breeds and humans there. So when the Breeds discover that someone has been stealing information from inside Sanctuary and slipping it to various pharmaceutical companies who wish to find out why Breeds who find their mates and mate with them stop or severely slow down their aging, they bring in troubleshooter Ria Rodriguez to massage the data and find out who exactly has been letting the information slip.

But it's not that easy to discover- nobody knows how the information has been getting out or who is responsible, but Ria is especially gifted in the area of codebreaking, and if someone is getting reports out- no matter how, she'll find it and backtrack it to the culprit.

Mercury Warrant is assigned to Ria as her bodyguard while she is in Sanctuary- since this operation is so secret it's a sure bet that whoever is doing this doesn't want anyone finding out, and so Ria's life could be in danger from the mole. But Mercury is frustrated by what he sees. Ria is a beautiful woman, but the way she dresses herself and carries herself hardly allows that to show. It's as if she wants to disappear- to brand herself into the worst sort of "ultra-plain, shushing librarian" sort of person.

Mercury is attracted to Ria despite the plain outward image she tries to project, but he's the perfect one to guard her. After all, he lost his mate many years ago back in the Labs, and his mating heat would be dangerous for any woman- the last time he went into it, he went so wild that he had to be sedated, and he killed several workers who got between himself and the woman who was his mate. It was so bad that the lab had to find a suppressing hormone to tamp down on his mating before he went completely feral and wild- so even if Ria was Mercury's mate, he could kill her, a defenseless human, if she proved to be his.

At least, that's what Sanctuary's Doctor is worried about. She was in the Labs where Mercury was born and lived, and she doesn't want Ria's death on her conscience. As Mercury grows more attatched and attracted to Ria, she has to worry about what could happen- and her own growing mental pain. But when Mercury's old mate shows up in Sanctuary, alive and wanting Mercury back, Ria again feels the pain of being second best, of losing someone who was interested in her- which Mercury swore never to make her feel.

Can Mercury show her that it's her he's interested in, not his old mate, and keep the promises he made her to love and want only her? What does Alaiya, Mercury's old mate, have to gain by showing up now? And can the breeds save Ely, the Sanctuary Doctor, from her increasing pain and mental breakdown? Who is Ria, really? And is there any kind of future for her and Mercury?

The Breeds suffer under some fairly strict mating rules- they have one mate, and that's it. There is only one woman for them. Even if they start a relationship with someone else, if their true mate comes along, the first relationship will have no luck and simply end. This is what Ria fears. She's already had an example of being second best, and it broke her heart so badly that she retreated into her role of being an unsexy, extremely forgettable nobody in the background. But beneath the surface of the woman who lives only for her job is a sexy, red-blooded woman who wants to be someone's one and only- but who has been too hurt to even try and reach for it.

Mercury comes into the book with some significant baggage of his own. How can he live with the fact that his mating heat causes him to become a violent, rage-filled beast? In the past, his mating heat was forced down with drugs. And they did so, but had another effect as well- the beast inside, the part of a Breed that gives them enhanced senses and enables them to mate- was so damaged that it nearly killed the beast inside. As it is, his senses are little better than a human's, and he, too, is reluctant to find his mate- the last thing he wants to do is hurt someone he loves.

But when he finds Ria, there is no hint of a mating heat. Not at first. Even if Ely is so scared of what might happen if Mercury falls into another mating heat, though, he can't stay away from Ria. He worries at her, pushing her out of her comfort zone, and when he learns why she is so gun-shy when it comes to romance, he promises never to break her heart. But will his former mate cause him to do just that? Not if Ria has anything to say about it! Indeed, her relationship with Mercury does more than finally open her heart to love- it reveals a secret that Ria never knew about herself.

I loved this book for the way that both characters were so damaged by their past relationships, and both had to find a way to move on and accept love into their lives. And not just accept it, but fight for it and treat it as something worth having, something that they would give everything for. Both characters must grow- sometimes in surprising and different ways, to gain the love they both want, but cannot admit to wanting, even to themselves. Recommended.