Tarzan, the king of the jungle, enters an isolated country called Minuni, inhabited by a people four times smaller than himself. The Minunians live in magnificent city-states which frequently wage war against each other. Tarzan befriends the king, Adendrohahkis, and the prince, Komodoflorensal, of one such city-state, called Trohanadalmakus and joins them in a war against the onslaught of the army of Veltopismakus, their warlike neighbours. Tarzan is captured on the battle-ground and taken prisoner by the Veltopismakusians. The Veltopismakusian scientist Zoanthrohago conducts an experiment reducing Tarzan to the size of a Minunian, and the ape-man is imprisoned and enslaved among other Trohanadalmakusian prisoners of war. He meets, though, Komodoflorensal in the dungeons of Veltopismakus, and together they are able to make a daring escape.