Second in the Cal Leandros/Nightlife series by Rob Thurman...
So now the guys have a couple more people in their lives that they care about, and they think they bad guys that have been stalking them since Cal was born are all gone so they think they can settle down a bit and try to have a "normal" life. Of course this doesn't go well, but you knew that already.
One of their new friends disappears and they end up having to find a specific object in order to get her back. And there's all kinds of interesting "people" along the way.