Chasing Bigfoot's origin story, Phil and Jessica uncover a rash of recent sightings and bone-chilling new evidence in the Pacific Northwest. New leads about a frightening encounter send them into rocky, dangerous terrain along Mount St. Helens.

Jess and Phil's investigation into the phenomenon of unidentified submerged objects off the coast of Catalina Island intensifies after the discovery of an extraterrestrial underwater base between the island and the mainland.