Rogue Elements by Karen Chance

Someone is kidnapping werewolves, and not just any wolves at that: every one is the daughter of an important clan leader. Desperate to find his daughter, Sebastian Arnou does the unthinkable: he goes to the Silver Circle of light magic users for aid. Their version of a police force is known as the War Mage Corps, and although they agree to help, few have much experience with Weres. The exception is disgraced, on-the-edge-of-being-canned war mage Lia de Croissets, whose mother happened to be a high-ranking member of the important Were clan Lobizon.

Someone with a werewolf mother isn’t much trusted by the Corps, and a mage with a human father is equally suspect as far as the clans are concerned. But her knowledge of Were customs and her background in human magic make Lia unmistakably the best person for the job. Whether they will be enough to keep her alive is another matter.