The stories in Llana of Gathol have a somewhat more humorous tone than earlier entries of the Barsoom series, and this book is considered to be an example of Burroughs engaging in self-parody late in his career.

The stories in this collection revolve around John Carter's granddaughter Llana of Gathol, who plays the "damsel in distress" role played by Dejah Thoris and Thuvia in earlier entries of the Barsoom series.

In search of solitude, John Carter flies to the deserted city of Horz.

By one of those coincidences which are common in Burroughs's books, he discovers his own granddaughter, Llana of Gathol, who is being held captive.

They meet an ancient, mad hypnotist who has preserved people for nearly a million years by the power of hypnotism.