The story of one demon doctor, his hospital and the slayer that tries to kill him, but in the process they both fall in love (although they both try to deny it) and live HEA. Simple really.
Eidolon is a Seminus Demon (an incubus), a doctor who lives for his hospital. He's approaching "The Change", which means if he doesn't bond with a female soon he'll turn into a raging demon - raping and killing anything female that he comes across.
Tayla is a Guardian - part of the Aegis that tracks down and kills demons, she's taken into Eidolon's hospital one night and it all goes from there. Yes, there's a fair amount of sex in this book, but there's also a lot of whining, whinging, demon soul searching. I'm sorry, but I like my demons scary, angry as f**k and willing to kill just about anything and anyone. Good demons???
Of course, true love never runs smooth and of course it's discovered that Tayla is half demon and that half is going to kill her if she doesn't integrate it. We also find that Tayla was present at the killing of one of Eidolon's brothers 2 years earlier, but that doesn't stop them from banging away at each other.
I'm not running out to buy the next book, but I'm sure I will read it at some point.