The story was first published as a seven part serial in Argosy All-Story Weekly beginning in December 1922; and then as a complete novel by A.C. McClurg & Co. on March 24, 1923.

[1] The story picks up with the Clayton family: Tarzan, Jane Porter and their son Korak, returning from their adventures in the previous novel (#8).

As a contingency to discourage any local denizens from questioning them, she seeks out and finds a Tarzan look-alike named Esteban Miranda to accompany them.

His Greystoke estate has become so financially depleted due to his support of the Allies war efforts, and he concludes it was time to return to Opar for another withdrawal.

Queen La, who has come into disfavor with the high priest, feels she has nothing to lose by escaping with Tarzan through the only unguarded route — a path to the legendary valley of diamonds, from which no one has ever returned.