This audiobook is narrated by an AI Voice. On the last isle of Poseidonis, in a marble house above the sea, the sorcerer Avyctes and his pupil Pharpetron have gathered every art that Atlantis remembers. Nothing in the known cosmos frightens them any longer.

A storm casts up a tablet of unknown metal, graven in a script older than the serpent-men who ruled before mankind. It takes them a year to decipher it. Pharpetron begs his master to leave it alone. Avyctes performs the invocation exactly as written, and nothing whatever happens.

Days later Pharpetron notices that his master's shadow no longer matches him. Something is lying alongside it on the floor, and each day it is a little closer.

Written as a warning by a doomed man in the hours he has left, The Double Shadow was Clark Ashton Smith's own favourite among his stories: a slow, immaculate, inescapable horror, and one of the finest things ever written about curiosity that cannot be taken back.