The ape-man stood with brows contracted in thought. It was evident that these apes really believed that they had seen him kill their fellow. What was the explanation? How could it be accounted for? Did the naked footprints of the great white man whom he had been following mean more, then, than he had guessed? Tarzan wondered. He raised his eyes and again addressed the bulls. “It was not I who killed Gobu,” he insisted. “Many of you have known me all your lives. You know that only in fair fight, as one bull fights another, have I ever killed a Mangani. You know that, of all the jungle people, the Mangani are my best friends, and that Tarzan of the Apes is the best friend the Mangani have. How, then, could I slay one of my own people?” “We only know,” replied the old bull, “that we saw you kill Gobu. With our own eyes we saw you kill him. Go away quickly, therefore, or we shall kill you. Mighty fighter is Tarzan of the Apes, but mightier even than he are all the great bulls of Pagth. I am Pagth, king of the tribe of Pagth. Go away before we kill you.” Tarzan tried to reason with them but they would not listen, so confident were they that it was he who had slain their fellow, the bull Gobu. Finally, rather than chance a quarrel in which some of them must inevitably be killed, he turned sorrowfully away. But more than ever, now, was he determined to seek out the slayer of Gobu that he might demand an accounting of one who dared thus invade his life-long domain. Tarzan trailed the spoor until it mingled with the tracks of many men—barefooted blacks, mostly, but among them the footprints of booted white men, and once he saw the footprints of a woman or a child, which, he could not tell. The trail led apparently toward the rocky hills which protected the barren valley of Opar. Forgetful now of his original mission and imbued only with a savage desire to wrest from the interlopers a full accounting for their presence in the jungle, and to mete out to the slayer of Gobu his just deserts, Tarzan forged ahead upon the now broad and well-marked trail of the considerable party which could not now be much more than a half-day’s march ahead of him, which meant that they were doubtless now already upon the rim of the valley of Opar, if this was their ultimate destination. And what other they could have in view Tarzan could not imagine. He had always kept closely to himself the location of Opar. In so far as he knew no white person other than Jane, and their son, Korak, knew of the location of the forgotten city of the ancient Atlantians. Yet what else could have drawn these white men, with so large a party, into the savage, unexplored wilderness which hemmed Opar upon all sides?