The main character in the story is a young man who discovers a series of notes left to him by his uncle, along with an "unnatural" sculpture. His investigation of these notes leads to the discovery of mysteriously similar cults that worship the same being as portrayed in the sculpture, who they call Cthulhu, said to be an ancient being from before the dawn of humanity that now sleeps in the sunken city of R'lyeh, waiting for the time to rise again, in both Alaska, and New Orleans. At the same time he discovered that artists all over the world, including the man who made this sculpture had been having dreams involving a "monstrous, cyclopean city" and the words Cthulhu and R'lyeh, which culminated on the night of the second of April.