Otherworld (Yasmine Galenorn)

We're the D'Artigo Sisters: Half-human, half-Faerie, we're savvy--and sexy--operatives for the Otherworld Intelligence Agency. But our mixed-blood heritage short-circuits our talents at all the wrong times. My sister Camille is a wicked-good witch whose magic is as unpredictable as the weather.
My sister Menolly is a vampire trying to get the hang of being undead. And me? I'm Delilah. When I'm under stress, I transform into a tabby cat--and a chance meeting with a stray cat leads to a mysterious discovery on our land, one that makes us realize that a looming shadow seems to be forming in our future. . .
There's a grumpy old gray tabby living on our property we name Cromwell. After some hissing, he and I become friends. I care about him and start feeding him, and one night we head out for a mouse hunt. . . but as we run through the woods, something catches my eye.
It's a mysterious stone, and I sense a dark magic coming from it--a dark magic that has coyote shifter written all over it. But when we find out who left it in our woods, we realize that our lives are never going to be the same.