I was lucky enough to grab a signed copy of Marked at one of the signings at the Dallas conference and I am sooooo glad I did. This is a flat out awesome book (and I'm not just saying that because I think PC Cast rocks.)
This is a young adult book but like with Stephenie Meyer's Twilight, you shouldn't let that stop you. Marked has a very smart, likeable heroine, a cool, dark world, and more than enough mystery to carry the series. (As a sidenote, while comparisons with Twilight are probably inevitable because both books deal with the vampire myth, they're two very unique (and wonderful) stories).
Basically, in the world of Marked, vampires exist. At a certain point in adolescence, it becomes obvious whether you're going to become one or not. That's when you leave your old life behind and enter the House of Night, where you learn to live your new life. The catch is, not everyone makes it through the Change. To make things even more complicated for our heroine, Zoey Redbird, the vampire goddess Nyx has given her special abilities and dark things are afoot in the House of Night.
I thought that premise sounded very intriguing and the book didn't let me down. Highly recommended. Check out PC's website for more info. (The book is co-written with her daughter, Kristin, who is just adorable. I probably shouldn't call another author adorable, but Kristin was so cute!).