We drove through open wrought-iron gates and into a brightly lit courtyard in front of the huge, hacienda-style, adobe house that served as home for the Tri-Cities’ seethe. Warren pulled his battered truck behind a BMW in a circular drive that was already full of cars.

Last time I’d been here, I’d come with Stefan. He’d taken us by the back way into a smaller guest house tucked into the backyard. This time we walked right up to the front door of the main house and Warren rang the doorbell.

Ben sniffed the air nervously. “They’re watching us.” I smelled them, too.

“Yes.” Of the three of us, Warren was...