Paula returns to her hometown of Shasta, California, to uncover the truth about her father's disappearance when she was a child. Her parents were fringe scientists investigating a mysterious horn -like sound heard all over the world. When her childhood friends find out she is back they join in and travel deep into the eerie woods around Mount Shasta, and are held captive by unexplainable forces beyond their control, and challenge their very understanding of the nature of reality itself.