Demon Mistress: An Otherworld Novel. Otherworld, #6

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 Delilah transforms into a tabby cat at the worst possible times. And me? I'm Menolly, acrobat-extraordinaire-turned-vampire.
And if the nerds from hell don't get their act together, I'm going to turn their toga party into a bloodbath... Life's getting stranger by the minute. First, Iris and I unearth a diary from one of the bartenders at the Wayfarer who disappeared under mysterious circumstances. And when I discover a ghoul in the woods near our home, we know there has to be a necromancer nearby--another sign that something's wrong.
But the blood really hits the fang when we discover a secret society bent on winning Shadow Wing's favor. Now it's up to us to stop the chaos they've unleashed on the city, and to prevent the demon they summoned from devouring Delilah's soul...