Encircled by an impenetrable thorn forest live the Alali, a tribe of primitive, Stone-Age giants with strange laws more savage than those of the jungle. Within the vast thorn boma also are the various tribes of the Minunians—eighteen-inch people with a high order of civilization, living in their complex, beehive like homes, fighting their savage wars on a miniature scale.

Tarzan is captured by the Alali and makes his escape, but he is taken prisoner in one of the numerous battles of the little warlike people. Even his enormous strength and vitality quail beneath the tasks the Minunians set him, and he has to use all his jungle cunning to save his life and prove his eventual friendship for the courageous pygmy tribes.