Tarim, the spiritual leader of Sun Mai, is dying, and his brother Khan plots to take over and make his own son the successor. But the true heir, Kashi, living in a distant monastery, summons Tarzan to escort him to Sun Mai to claim his throne. When Tarzan arrives from Africa, the monks subject him to tests of skill, wisdom, and strength to prove that he really is Tarzan. With the monks satisfied, he begins his journey with Kashi and Cho-San, his nursemaid. Along the way, Khan's men attack, Tarzan is separated from the boy and his nurse, and those two are captured. Tarzan rescues them, however, and they arrive safely at their destination. Khan does not dare slay Kashi; but according to law, he can still challenge his right to rule through tests of skill. The boy passes three tests; but the fourth, a test of might in which he would be pitted against the mighty Khan himself, causes him to select a defender in his place. He chooses Tarzan. Tarzan and Khan fight with knives on a net over a pit of burning coals, and Tarzan emerges the victor. Kashi can now be crowned ruler by his people, and Tarzan returns to Africa.