A paranormal writer receives a panicked email from a man who claims creatures are harassing his family.

The team finally arrives in Hellier and a stunning revelation shifts the case into the realm of wider fringe phenomena.

The search deepens as the team begins their investigation. A fellow researcher confirms the team's sense that something is paying attention to them.

The team pulls out all the stops on their search before receiving an extraordinary greeting.

The team look for answers in the abandoned tunnel before heading home, where they try to make sense of it all.