Full Moon Rising by Keri Arthur

This book is the first in the Riley Jenson series. These books have plenty of adult content, if that's what you're looking for.

Riley lives in Australia and works for the Directorate of Other Races. Her boss is a vampire. Riley? Well, she's part werewolf. She's also part vampire. She lives with her twin brother Rhoan. She's a liaison for Guardians--the operatives who hunt down rogue vampires and werewolves. Her brother is a full-blown Guardian, and her boss wants her as a Guardian, too.

Riley, however, is looking for a mate, one that she can promise herself to under the moon. She has two werewolf mates to help with the monthly moon heat that all werewolves have to cope with. Then, she meets Quinn, an ancient vampire. Her brother is abducted, she is betrayed, and Riley is drawn further into Directorate business than she wants to be.

Riley Jenson is a strong female character that you will root for. She is believable, and you feel for her dilemmas. Arthur draws you into the action, and you can't put the book down. It's a real page turner, and you'll be driven to find out what happens to Riley and Rhoan. Definitely a must-read book!