"Let's get this straight," insisted Doc Champ. "You say you are a refugee from the Ice Age? But that was some five hundred thousand years ago. And you are in possession of at least two instruments of advanced science. It doesn't match up." "It is quite necessary that you believe me." Rog Tanlu wasn't smiling now, but was speaking very seriously. "Perhaps you realize that it is a trait of the human mind to look upon the Past as uncultured. Such an attitude is greatly in error." "You traveled here through Time?" asked Doc. "Not exactly," said Rog Tanlu. "Time, as you know, is merely the illusion experienced by creatures endowed with memory living in a universe of random energy distribution. Time is movement, the rearrangement of matter--dependent upon the degree of entropy. I found it impossible to travel in Time. That's why I constructed the Ice Stone." "The Ice Stone!" There was a kind of awe in Doc's voice. "_You_ built the Ice Stone?" Rog Tanlu nodded. "Of course I didn't call it that. But I happened to overhear a conversation between you two, with the audio-visiscope, some days ago, and thereby learned the name you have for it. A very appropriate name! I also learned that neither of you had ever seen it. So now, if you will accompany me, I will take you to my laboratory--or rather to what still remains of my laboratory--and show you the Ice Stone. That should simplify things, and may help us to solve the problem of this impending migration--a problem which was forced on me due to certain interference, as I will later explain." He picked up that flashlight thing and started off up the creek bank. Doc Champ shot a glance at me as he wiped beads of perspiration from his face with his old felt hat. The shiny black locks plastered down on his head glinted as he stepped into the sunshine. "Come along," he said to me. "We'll see this through." We followed Rog Tanlu. Presently he turned off the bank of the creek, and the path he chose got rocky and wild as hell. I began to understand why it was that so few people had ever run across the Ice Stone by accident. "Doc," I whispered, "what do you make of this guy? Did you ever hear such a crazy yarn?" "You forget," muttered Doc, "that we saw some things, too." I knew what he meant. You couldn't get around that buzzard tumbling out of the sky, nor the mullah's image and voice in that silver globe. Rog Tanlu was walking a few yards ahead of us. Suddenly I saw a queer-looking object hanging in one of those scraggly trees that were having a hard time trying to grow there among the rocks. It looked like a heavy blanket or garment, the same fawn-color as Rog Tanlu's outfit. He stopped just opposite the tree where the thing was hanging from a low branch.