For long minutes I sat on the couch unmoving, my body numb with shock, my mind spinning in turmoil.

You wiped out my race… your people killed mine… and I will avenge my race by destroying yours — and your masters as well.

It couldn’t be true. And what did he mean by his talk of the two of us moving on different time tracks, of having met before? Your masters? What did he mean by that? Ormazd? But he said masters, plural. Is Ormazd the representative of a different race, an alien race from another world that controls all of humankind? Just as Ahriman is the last survivor of an alien race that we humans battled so long ago?

How many times had we met before? Ahriman said that this point in time, this first test of the fusion reactor, marked a nexus tor the human race. If it succeeds, we will use fusion energy to reach out to the stars. If it fails, we will kill ourselves within a generation. There must have been other nexuses back through time, many of them.

Somewhere back along those eons there was a war, The War, between the human race and Ahriman’s kind. When? Why? How could we fight invaders from another world back in the past, thousands of years ago?

All these thoughts were bubbling through my brain until finally my body asserted itself on my conscious awareness.

“It’s getting hot in here,” I said aloud.

My attention snapped to the present. To this tiny cell. The air was hot and dry. My throat felt raw. The room was now hot enough to make me sweat.

I got up and felt the nearest wall. It was almost too hot to touch. And although it looked like wood paneling, it felt like stone. It was an illusion, all of it.

One small step for a man… if he truly understands the way the universe is constructed.

I understood nothing. I could remember nothing. All I could think of was that Ahriman was back on Earth’s surface, up in Ann Arbor, working to turn the CTR into a mammoth lithium bomb that would trigger the destruction of the human race. And I was trapped here, thirty miles underground, about to be roasted like a sacrificial lamb on a spit.

You are only a step away from the house in Ann Arbor, he had said. Was that a lie? A joke? His idea of a cruel taunt?

“One small step for a man,” I muttered to myself. How is the universe constructed? It’s made of atoms. And atoms are made of smaller particles, tiny bits of frozen energy that can be made to thaw and flow and surge…

This room had been created by warping the energies of the atoms in the Earth’s crust. Those energies were now reverting back to their natural form; slowly the room was turning back into hot, viscous rock. I could feel the air congealing, becoming hotter and thicker by the second. I would be imbedded in rock thirty miles below the surface, rock hot enough to be almost molten.

Yet I was only a step from safety, according to Ahriman. Was he lying? No, he couldn’t have been. He had walked directly through the rock wall of this room. He must have returned to the cellar of the house inAnn Arbor. If he could do it, so could I. But how?

I already had!I had stepped from the cellar into this underground dungeon. Why couldn’t I step back again?

I tried doing it and got nothing but bumps against solid rock for my efforts. There was more to it than simply trying it.

But wait. If I had truly traveled thirty miles through solid rock in a single step, it must mean that there is a connection between that house and this chamber. Not only are the atoms of Earth’s crust being warped to create this cell, but the geometry of space itself is being warped to bridge the thirty-mile distance.

I sat on the couch again, my mind racing. I had read magazine articles about space warps, speculations about how someday starships would be able to fly thousands of lightyears almost instantaneously. Astrophysicists had discovered “black holes” in interstellar space that warped space-time with their titanic gravitational fields. It was all a matter of geometry, a pattern, like taking a flat sheet of paper and folding it into the form of a bird or a flower.

And I had seen that pattern! I had gone through it on my way into this chamber. But it had happened so quickly that I could not consciously remember it in detail.

Or could I?

Data compression. Satellites in orbit can accumulate data on magnetic tapes for days on end, and then spurt it all down to a receiving station on the ground within a few seconds. The compressed data is then played at a much slower speed by the technicians, and all the many days’ worth of information is intact and readable.

Could I slow down my memory to the point where I could recall, miscrosecond by microsecond, what had happened to me during that one brief stride from the house to this underground tomb? I leaned back on the couch and closed my eyes. It was getting more and more difficult to breathe, but I tried to ignore the burning in my chest and concentrate on remembering.

A thirty-mile stride. A step through solid rock. I pictured myself in the cellar of that house. I had ducked under a heating pipe and stepped into darkness…

And cold. The first instant of my step I had felt a wave of intense cold, as if I had passed through a curtain of liquefied air. Cryogenic cold. Cold so intense that atoms are frozen almost motionless, at nearly absolute zero temperature.

In those few microseconds of unbearable cold I saw that the crystal structure of the atoms around me had indeed been frozen, almost entirely stilled. All around me the atoms glowed dully like pinpoints of jeweled lights, faint and sullen because nearly all their energies had been leached away from them. The crystal latticework of the atoms had formed a path for me, a tunnel wide enough for my body to take that thirty-mile-long step in a single stride.

I opened my eyes. The tiny room was glowing now; the air itself seemed afire. I held my breath, wondering how long my body could function on the oxygen stored within its cells and in my blood.

I understood how I had gotten here. There was a crystal latticework of energy connecting this crypt with the house in Ann Arbor — a tunnel that connected here with there, using the energies stolen from the atoms in between to create a safe and almost instantaneous path between the two places. But the tunnel was dissolving just as this room was dissolving. The energies of those tortured atoms was returning to normal. In seconds all would be solid rock once again.

How to find the opening into that tunnel? I concentrated again, but no sense of it came through to me. I was sweating, both from the intense heat and from the effort of forcing myself to understand. But it did no good at all. My brain could not comprehend it.

My brain could not… Wrong! I realized that I had so far been using only half my brain to attack the problem. I remembered Ormazd telling me that I could consciously employ both hemispheres simultaneously, something that ordinary human beings cannot do. I had been using one hemisphere to visualize the geometric pattern of the energy warp that connected this underground chamber with the surface. But that half of my brain could only perceive geometrically those relationships involving space and form.

With a conscious effort I forced the other hemisphere of my brain to consider the problem. I could almost hear myself laugh inside my head as the unused portion of my mind said something like, “Well, it’s about time.”

And it was about time. The solution to the problem of finding the gateway to the crystal latticework of atoms was a matter of timing. All those dully glowing atoms were still vibrating slowly, unnaturally slowly, because most of their energies had been drained from them. But still they vibrated. Only when they had all moved to a certain precise formation was their alignment such that the tunnel’s entrance could open. Most of the time they were shifted out of phase, as unaligned and jumbled as a crowd milling through a shopping mall. But once every second they reached precisely the correct arrangement to open the tunnel that led back to safety. The arrangement dissolved within a few microseconds.