Badlands - Douglas Preston, Lincoln Child

In the New Mexico desert badlands, a woman's skeleton is found with two rare artefacts clutched in her hands: lightning stones used by the ancient Chaco people to summon the gods. Was it suicide... or sacrifice? FBI Special Agent Corrie Swanson brings in archaeologist Nora Kelly to investigate. When a second body is found in identical circumstances, they realise the case runs deeper than they imagined. As Corrie and Nora pursue their investigation into remote canyons, haunted ruins, and long-lost rituals, they find themselves confronting a dark power that, disturbed from its long slumber, threatens to exact an unspeakable price.