At the Mountains of Madness is a science-fiction novella written by H. P. Lovecraft in 1931 and published in Astounding Stories in 1936. Like much of Lovecraft’s work, it also helped establish the genre of cosmic horror, or what Lovecraft called “weird fiction”: horror that relies on existential anxieties about humanity’s place in the universe to achieve its effects. The story involves a research team discovering an ancient city buried beneath the Antarctic. At the Mountains of Madness has been adapted into graphic novels, video games, and other media. This guide uses an e-book version of the novel, which is now in the public domain.

Plot Summary

William Dyer is a geologist and a professor at Arkham’s Miskatonic University. He writes in the first-person perspective, hoping to warn people not to venture to Antarctica. A research team is planning such a trip, and Dyer shares his own terrible experiences to persuade them not to go.

Dyer’s initial experiences are routine. The team sails south from Boston with plenty of manpower, equipment, and excitement. They reach Antarctica a month later and begin to search for their landing place. The science teams make camp and begin to explore. One of the scientists, Professor Lake, has an urge to explore a distant part of the region. He takes a team and a plane, radioing back excited messages about a discovery that has the potential to change the world. The rest of the team gather around the radio and listen to Lake’s claims that he has discovered the remains of more than a dozen unknown life forms. Some of these life forms seem damaged or injured, but eight are perfectly preserved. They are something between plant and animal, with strangely shaped bodies, numerous tentacles, and wings. Lake believes that they even have the capacity to use tools, but their existence does not fit into any established idea of how life on Earth formed.

As the rest of the expedition prepare to join Lake, they lose contact with his team. They fly out to his base but arrive to discover that a terrible accident has occurred. One man and one dog are missing; all the rest are dead. The wounded creatures seem to have been buried, while the pristine specimens have vanished from the ransacked camp. Dyer and his team try to convince themselves that perhaps the men lost their sanity and killed one another, but they are overcome by a sense of dread.

Dyer and a student named Danforth take one of the planes and explore the nearby mountains. They discover a strange city hidden behind the gigantic mountain range. The architecture of the city does not resemble anything in the human world, but it reminds Dyer of ancient beings described in mythology as the “Old Ones.” Dyer and Danforth land the plane and begin to explore the abandoned, crumbling city. Dyer establishes that the buildings are many millions of years old. By examining the carvings and murals in the buildings, Dyer learns about the history of the Old Ones. They came from space and colonized Earth tens of millions of years ago. They used their intelligence to create artificial lifeforms named Shoggoths, which they used as a slave workforce to construct many cities. These Shoggoths were made of black slime, covered in hundreds of eyes, and had the ability to take any form. The Old Ones took over Earth, farmed new life forms for food, fought against other invading species, and even put down a Shoggoth rebellion. Eventually, they retreated to their city in Antarctica and then into the subterranean ocean below the continent. Their history also hints that an even more terrible life form lives in even taller mountains on the horizon.

Dyer and Danforth are filled with a sense of dread but continue to explore. They soon realize that the Old Ones that Lake discovered returned to life and killed everyone in Lake’s camp. They find the bodies of the missing man and dog. As they try to explore the underground tunnels, they discover a number of giant blind penguins that the Old Ones once used as a food source. In one tunnel, they find an Old One that a Shoggoth has killed. The Shoggoth chases them out of the tunnels, and they escape to the plane. As they fly away, Danforth looks back at the city. He experiences a vision implied to be of the great evil lurking in the distant mountains. The vision eventually drives him insane.

Dyer finishes his account with a warning. He believes that the Shoggoths destroyed the Old Ones’ civilization, and that the evil in the hidden parts of Antarctica is too much for humans to bear. He warns anyone planning an expedition to reconsider.