Miskatonic folklorist Albert Wilmarth exchanges letters with Vermont farmer Henry Akeley, who insists the fungoid Mi-go are mining the hills and preserving human brains in metallic cylinders for transport across the cosmos. Wilmarth eventually visits the farm, where the truth proves more unsettling than any letter.
Widely regarded as one of Lovecraft's finest longer tales, it merges epistolary tension with scientifically framed cosmic horror. The Mi-go become one of the Mythos' most enduring alien species.