Holding your knife with its long ivory blade pointing upward, you advance very slowly, step by step, toward the wolf, which stands growling softly, apparently confused by your boldness.

Then it springs. You lunge with your knife, twisting your body to avoid its awesome fangs. Your knife cuts through nothing but air, but the wolf succeeds only in tearing off your bearskin coat. It stops for an instant to sniff at the coat, and you turn and plunge your knife into its neck. The wolf twists, looks at you with hate in its eyes, and falls limp, its spinal cord severed.

Now you are a true Stone Age hunter. You skin the wolf and walk into the cave.

You follow the right-hand tunnel, thinking you may find your way back to your own time, but suddenly you feel yourself falling-faster and faster into what seems a bottomless pit.

Suddenly you hear voices shouting. You hide in a thicket. An animal crashes through the brush. In a moment some men rush by in pursuit, carrying spears and slings. You imagine that you must be in an era long before the advent of civilization. You follow an animal trail; it soon leads to a clearing, and you lie down in the grass to rest. Looking up in the sky, you see a long, thin, white streak. You rub your eyes and look again. It seems to be a vapor trail from a jet plane! You may be living in the present time after all.

After several days of wandering through the jungle, you reach a settlement on the banks of a large river. There is an airfield nearby, and within a few weeks you are able to obtain a ride back to civilization and return to your family-just a month after you first entered the Cave of Time. You are happy to be back home, but shocked at how much older everyone looks. And they express the greatest surprise that after eleven years you haven’t changed a bit!