The story is recounted by the protagonist, Comte Antoine de C-, in the first person. Hundreds of years ago, Antoine's noble ancestor was responsible for the death of a dark wizard, Michel Mauvais. The wizard's son, Charles le Sorcier, swore revenge on not only him but all his descendants, cursing them to die on reaching the age of 32.
The story begins with the narrator describing the night sky as observed over long sleepless nights from his window, in particular that of the Pole Star, Polaris, which he describes as "winking hideously like an insane watching eye which strives to convey some strange message, yet recalls nothing save that it once had a message to convey".
The story revolves around a Bostonian painter named Richard Upton Pickman who creates horrifying images. His works are brilliantly executed, but so graphic that they result in his membership in the Boston Art Club being revoked and himself shunned by his fellow artists.
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.