At a gathering to decide the fate of Randolph Carter's estate which has been held in trust since his disappearance the mysterious Swami Chandraputra, who wears curious mittens and enveloping robes, tells Carter's acquaintances of his ultimate fate. He explains that the key took Carter to a type of higher dimension.
A lighthouse keeper named Basil Elton engages upon a peculiar fantasy in which a bearded man piloting a mystical white ship is found sailing upon a bridge of moonlight. Elton joins the bearded man on this ship, and together they explore a mystical chain of islands unlike anything that can be found on Earth.
It is a recording of a dream, where the main protagonist is a Roman military official in the Basque country near Pompelo. The countryside is, every year, ravaged by terrible hill people who kidnap citizens and perform cruel rituals at a Sabbath. The narrator wishes to lead a military expedition to crush these hill folk, as a feeling of approaching evil has enveloped the countryside, due to a riot between the citizens and the hill people. These hill folk came to trade, yet some of these are killed and later, no disappearances occur before the time of the Sabbath. The incursion is guided by a local-born son of Roman parents.
Carter, a weird fiction writer, meets with his close friend, Joel Manton, in a cemetery near an old, dilapidated house on Meadow Hill in the town of Arkham, Massachusetts. As the two sit upon a weathered tomb, Carter tells Manton the tale of an indescribable entity that allegedly haunts the house and surrounding area. He contends that because such an entity cannot be perceived by the five senses, it becomes impossible to quantify and accurately describe, thus earning itself the term unnamable. As the narration closes, this unnamable presence attacks both Carter and Manton. Both men survive and awaken later at St. Mary’s hospital. They suffer from various lacerations, including scarring from a large horn-shaped object and bruises in the shape of hoof-prints on their backs.
The story involves a mine that uncovers a very deep chasm, too deep for any sounding lines to hit bottom. The night after the discovery of the abyss the narrator and one of the mine's workers, Juan Romero, venture inside the mine, drawn against their will by a mysterious rhythmical throbbing in the ground.
The story tells of an unnamed narrator, who has moved from New England to New York City and greatly regretted it. One night, while wandering an older part of Greenwich Village, he happens upon a man strangely dressed in garments from the eighteenth century. The man offers to show the narrator the secrets of the town.
The story is about a golden-haired youth who wanders into the city of Teloth, telling tales of the great city of Aira, where he was prince. While Iranon enjoys singing and telling his tales of wonder, few appreciate it. When a disenfranchised boy named Romnod suggests leaving Teloth to go to the famed city of Oonai (which he thinks may be Aira, now under a different name), Iranon takes him up on his offer.