Witchmate — Renee George

While robbing an art collector, Emma Watson finds herself trapped in an airtight vault with no way out...until she finds a spider key and a mysterious door that appears at the back of the room. The key fits, but instead of finding freedom on the other side, she finds herself in an unfamiliar world where the only two species, witches and wolves, are at war. Caught in the crossfire, Emma is sure her butt is fried... until a gorgeously wild man name Keir D'San shows up and carries her to safety.

Keir has spent his entire life fighting witches. In the middle of another battle with his bitter enemies, he comes upon a spirited woman who is neither a witch nor a wolf and rescues her. Their chemistry is instant and their attraction explosive. But when Emma develops magical abilities, Keir has to choose between his wolf shifter clan and the witchy woman who is his true mate. Old rivalries and betrayals set Emma and Keir on a dangerous path that may end up costing them their only chance for real happiness.