The Fever Series by Karen Marie Moning starts with Darkfever and ends with Shadowfever, with three books in between. The premise is spelled out nicely in Darkfever:
Darkfever (as taken from Karen Marie Moning's website):
The tagline for the Fever Series "Feel the heat, catch the fever." accurately describes my reaction to these books. Sure, it sounds very sexual and tense (it's a dark thriller dealing with Celtic Faeries, how can it not be?), but underneath that tagline are truly sympathetic characters, twisting plots, and edge of your seat writing. Reading this, I felt the heat of these factors and caught the fever of reading these books. I'm hooked.
The protagonist is one of the best female leads I've seen to date in genre fiction. I don't know if its my own Floridian heritage that makes me sympathize with her love for the sun or how she enjoys the slow life of the American South (not that my part of Florida really counts, but the attitude pervades everything), but this pretty-in-pink woman grabbed me from the start. She's blonde with a good body, but she comes alive on the page. She's not your Barbie stereotype, she's Mac, just Mac. Watching her go from Mac 1.0 to Mac 4.0 by the end of the series only served to latch me in further. An ordinary woman faced with these life altering choices and tragedies really makes you think and feel for this character.
The male leads: Jericho Barrons and V'lane, are not one-dimensional, sex-crazed hunks. The mysterious, tatoo-clad guardian figure is cold, sure, he's mysterious, sure, but he has some rare moments of genuine emotion that are as subtle as all his other actions. You watch parts of him peel away like a Shrek-onion (only better looking) to show how deep of a character he really is. And V'lane, the romantic, sex-crazed, heart throb faerie prince (yeah second most masculine thing in this book) shows little by little how human his true intentions are, despite the fact he's anything but human.
And the mythology! This woman's take on the folklore of the Scottish and Irish Celts is nothing short of unique. Her interpretation stays true to the character of the source material while taking on a radical life of its own. Celtic Mythology is what I want to write around, and throughout these books, I felt new inspiration to delve into my own work and make it this good.
This series will keep you guessing and invested the whole way through. You'll find yourself believing "Holy crap, the world really is in danger, Ireland really is where it's all going down, and MacKayla Lane really is our only hope."