Russell tracks a massive creature to a box river canyon but finds he can't escape a shadowy figure on the prowl. Bryce discovers Bigfoot is lured in by whistling, while Ronny and Mireya realize something is watching them from across their base camp.

The team ascends massive pine trees in search of evidence from above. Bryce uncovers government secrets that may include underground bunkers. A 3D image specialist discovers possible man-made structures deep in the forest and captures a ghostly image.