The deceased narrator, Francis Wayland Thurston, recounts his discovery of notes left behind by his grand-uncle,
Brown University linguistic professor George Gammell Angell, after his earlier death in the winter of 1926–27. Among the notes is a small
bas-relief sculpture of a scaly creature which yields "simultaneous pictures of an octopus, a dragon, and a human caricature." The sculptor, a
Rhode Island art student named Henry Anthony Wilcox, based the work on delirious dreams of "great
Cyclopean cities of titan blocks and sky-flung monoliths." Frequent references to
Cthulhu and
R'lyeh are found in Wilcox's papers. Angell also discovers reports of
mass hysteria around the world. More notes discuss a 1908 meeting of an archeological society in which
New Orleans police official John Raymond Legrasse asks attendees to identify a statuette of unidentifiable greenish-black stone resembling Wilcox's sculpture. Legrasse had obtained the sculpture the previous year, when he led a party of policemen on a raid into a swamp which surprised a bizarre
cult holding a
bacchanal ritual with human sacrifice. After killing five of the cultists and arresting 47 others, Legrasse learns that they worship the "Great Old Ones" and await the return of a monstrous being called Cthulhu. The prisoners identify the statuette as "great Cthulhu." One of the archaeologists consulted at the meeting,
Princeton professor William Channing Webb, had once encountered a group of "
Esquimaux" with similar beliefs and fetishes. The sinster import of the notes becomes clear when Thurston coincidentally comes across a 1925 article from an Australian newspaper which reports the discovery of a derelict ship, the
Alert, of which second mate Gustaf Johansen is the sole survivor. Johansen reports that he was originally aboard a second vessel, the
Emma, when it was attacked by pirates aboard the
Alert, a heavily armed yacht. The crewmen of the
Emma killed the pirates but lost their own ship in the battle, commandeered the
Alert, and discovered an uncharted island in the vicinity of co-ordinates of . With the exception of Johansen and another man, the remaining crew died on the island in a mysterious fashion. Upon traveling to Australia, Thurston views a statue retrieved from the
Alert which is identical to the previous two. After traveling to Norway, he learns that Johansen died suddenly after an encounter with "two
Lascar sailors". Johansen's widow provides Thurston with her late husband's manuscript which gives the true story of his voyage. He reveals that the uncharted island was a "nightmare corpse-city" called R'lyeh. Johansen's crew struggled to comprehend the
non-Euclidean geometry of the city and accidentally released Cthulhu, resulting in their deaths. Johansen and one crewmate fled aboard the
Alert pursued by Cthulhu, but they rammed the yacht into the creature's head, only for its injury to regenerate but allowing them to escape. Johansen's crewmate died as did Johansen soon after returning home. After reading the manuscript, Thurston realizes he is now a target of Cthulhu's worshippers, and hopes in vain that his horrible discoveries will never be revealed to the public. ==Inspiration==