When Amy Larson and her partner Hunter Forrest investigate a missing persons case in a series of caves outside Denver, Colorado, they discover a muddy pit littered with corpses that are covered in human bite marks and find the case leading them to a cult.

When a congressman's media assistant abruptly quits her job and goes missing on the way home, FBI agent Meg Murray teams up with special agent Matt Bosworth to investigate a serial killer with ties to a political conspiracy.