Tarzan and the Land Beneath the Earth

Tarzan, N'kima, Tantor, Buto, and Gorgos end up sucked underground by a forcefield and end up in the underground city of Terrapolis which is inhabited by the Mole People. Tarzan learns from Dr. Zolus that they have been using the Makos Trees in order to power their furnace when their own thermal vegetation has been used up. With help from the Mole Scientist Sedora, Tarzan must free his animal friends, prevent more Makos Trees from being brought to Terrapolis, and find a new source of power for the Mole People to use.