The Horned Ones — Christine Morgan

Cornucopia Caverns. A safe, fun, family-friendly show cave destination where visitors can enjoy guided tours of subterranean chambers and spectacular limestone formations in a nice cool reprieve from the California summer heat. Until the disaster. Until the rocks fall, and the blood flows, and the lights go out. Until three groups of tourists are trapped in the darkness, hoping for rescue, trying to find a way out, hoping to survive. But they aren't alone down there. The caverns reach deeper and farther than anybody knew. Something else hides in Cornucopia's depths. Something that's been waiting for an opportunity like this.