The story describe the appearance of Nyarlathotep as a "man" of the race of the Pharaohs, who claims to have been dormant for the past twenty-seven centuries, and his subsequent travels from city to city demonstrating his supernatural powers. Wherever Nyarlathotep went, the story relates, the inhabitants' sleep would be plagued by vivid nightmares.
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.