When a mysterious stone with strange writing on it is found in Vermont, Rex and Hannah rush to uncover the dark secrets behind it.
The events of this story are inspired by the H.P. Lovecraft story, The Whisperer In Darkness.
Randolph Carter, based on the Lovecraft character of the same name, makes his first appearance in this story.
This story marks the beginning of the shift towards the world of H.P. Lovecraft.
Susan, the Vanishing Hitchhiker ghost that Rex and Hannah help cross over, at the start of the story, is based on a character that appeared in the 1973 movie Encounter with the Unknown.