Tarzan's plantation is destroyed by invading German troops from Tanganyika.

With the speed of the great apes, Tarzan rushed through the jungle toward his home and family. But he was already too late. The marauders had been there before him. His farm was in shambles and no one was left alive. Of his beloved wife there was only a charred, blackened corpse, still wearing the rings he had given her. Silently, he buried the body and swore his terrible vengeance against those who had done this terrible deed. Then he set out grimly to track them --through warring armies -- across a vast desert that no man had ever crossed -- and to a strange valley where only madmen lived.