Something is terribly wrong in the nation's oldest national park. Horrific deaths have occurred throughout Yellowstone and everyone believes that a monstrous grizzly bear is on a rampage. Scientific evidence suggests another terrifying conclusion. For Chief Ranger Glenn Merrill, putting an end to the mysterious deaths is more than just his job, it is a mission that will take him to the brink of death and shatter the foundation of his beliefs. Apparition Lake plunges Glenn, his full-blooded Shoshone friend Johnny Two Ravens, and Jennifer Davies, an aggressive young biologist, into a world of Indian mysticism where mankind and nature struggle for control of Mother Earth. Apparition Lake races through its supernatural tale of an environment that has "had enough" and the Native American spirit it uses to mete out its revenge.

Mother Earth is crying. Yellowstone is dying. New troubles are stacking up like cordwood for Chief Ranger Glenn Merrill, as Yellowstone’s existence is threatened by earth tremors and an imminent super-volcano. After a series of gruesome deaths claiming animals, tourists, and a ranger, it’s clear that something’s gone terribly wrong at the nation's oldest national park. But putting an end to these mysterious deaths is more than just the chief ranger’s job—it may be his end. Obsidian Tears plunges Glenn, his Shoshone friend, an aggressive young seismologist and an Arapaho healer into a world of Indian mysticism. Will man and nature join forces, or risk losing all of humanity to an ancient evil?