Henry Akeley is a Vermont naturalist who discovers that the hills near his remote farm are inhabited by the Mi-go. He sends letters, photographs, and recordings to Miskatonic folklorist Albert Wilmarth.
When Akeley's correspondence abruptly turns cordial and invites a visit, Wilmarth travels there. He finds a strangely altered Akeley in an armchair — but realizes the figure is a constructed shell; the real Akeley's brain has been extracted and taken by the Mi-go.