 On the banks of a river in an uncharted section of the jungle, Tarzan and Darno and their four friends, Major Burton Ashley, Jeanette Burton, Dr. Wong Tai and Terrence O'Rourke, are captured by a strange race of yellow giants. They escape, taking to the river in a crude native dugout and are carried by the swift current into a dark tunnel. Hours later, they emerge into bright moonlight between precipitous rocky banks, which presently give way to jungle-clad shores. The current becomes momentarily swifter. Like the continuous crashing of giant breakers on a rocky shore, a deep booming sound warns Tarzan of a waterfall in the river beyond. Urging his companions to use their paddles, the ape man sets the example by exerting every ounce of strength in his mighty arms and shoulders in an attempt to pull the ungainly dugout to shore. Useless effort. The current holds the canoe in its mighty grasp, rushing it at ever-increasing speed, nearer and nearer to the brink of the booming cataract. As the dugout flashes beneath the overhanging vine-grate branch, Tarzan leaps upward, grasps a thick strand of creeper and swarms up toward the limb. Suddenly a cry of horror escapes the occupants of the canoe as they see the ape man drop like a plummet toward the river, clinging to one end of the broken vine. He's broken? He's falling into the river. No, no, no. See there? The other end of the vine. It holds. He is swinging toward the bank. He has at least saved himself. There is no possible way he can help us. We are doomed. Big hurry. Look at him run down the bank with the speed of a lion. My job is overtaking us. If he can, but to reach that tree there at the edge of the falls. With the speed of an antelope, Tarzan bounds along the rough bank toward a mammoth polar carpus tree that stands close to the river's edge and a few yards back from the brink of the cataract. One great lower limb sweeps far out over the river. Reaching the tree, the ape man springs upward, vanishes in the thick foliage. A moment later he reappears, running lightly out on the thick branch. He whips the grass rope from his shoulder, makes one end pass to a strong limb. As the dugout passes swiftly beneath him, he hurls the stout coils, so often tested against the savage strength of the mighty Numa, down into the outstretched arms of Darno and Rourke. The two men, backed by Ashley and Wong, cling to the rope with all their strength as the heavy dugout jerks to a standstill in the rushing current so near the edge of the cataract, the genet in the prowl, gassed as she stares terrified down over the brink of the waterfall. Hang on, men. Let hold one quick. If it will only hold against the pull of the current, do not worry about that. I have seen it hold the strongest beast in the jungle. All tight. I'm going to untie this end and pull you to the bank. Swiftly Tarzan loosens the rope, the muscles of his great arms and shoulders not into steel cords. Slowly, foot by foot, he makes his way along the great limb toward the river bank, pulling the dugout behind him. Savagely, the water boils and swirls around the canoe as though reluctant to give up its prey. As the craft touches the shore, the eight-man makes the rope pass to a tree, drops quickly to the ground and pulls the dugout halfway out of the water. Oh, I think she'd be to the saints. Faith and I'd rather take my chances with any yellow men than go through that again. By the cues of my venerable ancestors, Tarzan, thou art a man. Give me some water, one of his. Tenet's fainted. Father, the reaction was too much for this brandy, O'Rourke. Hey, here, my flask. Oh, will you look at that now? French brandy in the jungle. Pour a little in the top of the flask. Here you are, of course, sir. Drink this for Terry. I'm all right, Terry. I just couldn't talk. I was scared stiff. Sure, and I don't blame you. I'd drink this anyway. It'll do you good. Thanks, Terry. Ah, the rest of it. Ah, and she's only a draught. Stop it, Terry. Do you want to drown the girl? I'll leave they major. A little nip after what she's been through won't harm her. I could stand it. Me shall be, Gary. Oh, Donald, you and O'Rourke get some wood and start a fire. I'll pull the dugout up by the bank away from the water. I can't believe that we're safe on shore. Did you look down over the brink of those falls, Uncle Jim? I was terrible. Hundreds of these great jagged rocks down there. Well, my dear, don't think about it. I'd give them up hope myself. You rest, Norma Moselle. Tomorrow we shall find a way down the cliff to the river below. Benny, Mr. O'Rourke, we shall gather wood for the fire. Right, would you, Lieutenant? Uncle Jim. Yes, Colonel? What is it? Do you think we'll ever get out of that awful country alive? Why, of course. What made you ask that? Well, I don't know. I was just wondering. No, Lieutenant, my child. This experience, you could not dwell on such dark thoughts. I suppose not, but how can I help it? You're the man like Tarzan to see us through. Why, we're bound to come out always. It's nearly a matter of getting the dugout down to the river below the falls in the morning. Carrying on? Carrying on. Yes, I guess you're right. Come, come, Janet. As Long says, don't think of the unpleasant side of the situation. We'll get through right enough. Oh, but sometime one of us, maybe all of us, will fall into a situation that we can't get out of. It's impossible for Tarzan to be with everybody all the time. After all, he's only human. My dear, the old seeing who watches over us and points our destinies has led us out of danger so far. Is there any reason to believe he will be there thus far? Oh, I know, but this terrible cruel country, filled with every sort of danger and horrible death lurking behind each bush and every shadow, or even its ribbers. Our experience of a few moments ago has naturally unnerved you, Janet. If we exercise caution and trust to the leadership of Tarzan, I believe we shall have little to see, eh? There you are, my dear. Take a leap from the Frenchman for it. Apparently not a worry on his mind. Ah, bien, mes amis. You look contented enough there in the moonlight, almost as if you were listening to Les Conceux, mais j'ai d'en déplanté un tarry. Only, in this case, it is the chorus of the genre you are listening to. Ah, now for a little fire and everything will be ship-shaped in un moment. You are entirely over the effects of our, shall I say, late experience, no more version of this? Yes, Lieutenant, I'm fine. That's the spirit, dear. Chinon, eyes front. Where is Aurora, Lieutenant? Eh, with Tarzan, Michelin, doctor. Tarzan killed a steak and is bringing it in. A steak? I don't understand. Ah, what about my jaw? Ah, for sake of shows. Excellent eating. Look here, look at that, Tarzan. All of them waiting for their supper without a care in the world. And right after you pull them out of the jars of death, well, he'll be having it now. It'd better be good, Terri. Sure, and it will be major. How do you feel, Jeanette Cushlan? Oh, I'm firmish, Terri. Ah, then wait till you've had one of these worth of buck steaks, Tarzan. He says that they're the best eating in the jungle. Yes, outside the zebra. Zebra? You don't mean you've eaten zebra, Tarzan. Why not? In the jungle, the hungry animal, man or beast, eat what it can get. Oh, well, I couldn't eat them. This is not zebra, Mr. Net. Cut off as much as we can carry, Warlock. When it is seared, it will last several days. For myself, I shall eat. And if it does not fall to me to take the first watch, sleep. I must admit to being tired. You had better all rest. I'll take the watch. It'll be daylight soon anyway. Joe, I hadn't noticed. The moon is low in the sky. Almost touching those treetops over there. I shall stand the first watch when I'm in. The daylight is still several hours away. You rest, Darnell. I'm not tired. As the little company finishes its meal of waterbuck steak and each member of the group composes himself to rest, Tarzan swings lightly to the broad limb of the nearby tree and settles down with his back to the trunk. The moon drops swiftly behind the distant horizon, and inky blackness steals out of the jungle to envelop the sleeping camp. Crickets thicken the air with their shrilling and the forest crowds close. The far-off chatter of monkeys dies away. The hungry roars of Numa, Sheetan, Sabor drop to subdued, contented rumblings. As having killed and fed, the great jungle beasts seek their lairs to rest and sleep through the heat of the approaching day. The summits of the tall cliffs inspire's glow with the rosy light of dawn as Tarzan arouses the camp. Before the rising sun slants into the purple mists of the jungle, the eight men and his friends have finished their meager breakfast and are seeking a pathway to the river below the falls. Oh, Uncle Jim, what a glorious morning! Yes, things look a bit different from what they did last night, eh, my dear? No, just look back there. Why, that river gorge is beautiful. Those high red cliffs. The thing that we've seen that way. It did look weird and mysterious by moonlight as far as we know. And after coming through that carable black hole last night, it looked more beautiful than anything I'd ever seen. So the danger of that cataract took everything else out of my mind. Just look down there this time. Oh, suppose Tarzan had been unable to... I can't bear to think of it. Come on, Mr. Lett. Tarzan? Oh, it's Tarzan. Come on. Hello, ma'am. Let us go. Hey, Tarzan! Long! Major! Come here! Have a look at this! Now what? Carrie never yells like that unless he's excited about something. It's Kiliyat Tarzan. What have you found? A pot by Joe. Seems well-worn, too. Angling down the cliffside. Travelling used by the animals coming to the stream to drink. This is not an animal trail. But who else could have? Oh, look here. Further along. Animals don't cut paths through solid rock. Is that what you mean, Tarzan? Yes. That's what I was thinking. But if it takes us to the river below the falls and... Well, it seems to be leading in that direction. And that's what we're looking for. We can come back after the dugout. We'll follow it. Darno and I'll lead the way. Rourke, you bring up the rear and keep your eyes open. Right here. Lead on, then. I'll be watching the back frame. Come on, Darno. The rest of you stay close. Why are you very cautioned, Tarzan? You are not satisfied with the appearance of things? No. Ashley was right when he said animals don't cut trails through rock. They go round the easiest way. Then this pathway... Was made by men. Maybe for the same reason we're using it now to get round the falls. Men move. If human beings made this trail there should be some sign of them. There are. You mean footprints? I don't mean they ground closely and found none. Fair feet don't leave prints on rocks, Darno. But there are other signs, many of them. Broken bushes beside the path. Could have been done by some passing animal, Tarzan. No. Numa walks the path. He walks in the middle unless he's stalking prey. Then he slips to the bushes beside it. And he does not break twigs or fresh leaves. Oh, fine. You confirm. Then this pathway has been used and lately. Those leaves on the ground. Yes. Wish the wind were blowing toward us instead of at our back. You are uneasy, my friend? Yes. I feel as if I were walking into a trap. Here, wait. Something wrong, Tarzan? I'm going into the trees to look around. All of you stay right here. Be quiet. No, you're Tarzan. You're all right. We walked deliberately into an ambush. Voila! We are completely surrounded. Those fiendish yellow men. They followed us and... No, no, my child. You are wrong. They're beat by a joke. Two instead of claws. I'm going to drop that fellow coming up...