“I am unfamiliar with the term. Tell me, what was it like? Passing through?”

I shrugged and said, “I wasn’t really paying attention.”

John said, “Yeah, it wasn’t that great.”

The man waited for quite a long time for us to add something, but we did not. Finally he said, “We have been awaiting your coming, as you can see. We have worked for many years, suffered many tragic setbacks, in order to find and communicate with another plane such as yours. Some thought that travel from one to another was impossible, but here you are. Your world, you see, is a sort of twin to ours, an offspring born of the same litter.”

The man turned and gestured to the wall and the letter “Y” appeared in black. Suddenly I realized that the texture on the walls was moving and twitching and that it was not stucco or plaster. They were insects, clustered together to cover the entire surface of the room. They were the size of dimes and seemed to have the chameleon’s ability to change the color of their shells at will.

“Up until here,” said the man, pointing to the place where the trunk of the “Y” split into two branches, “our histories were identical. This spot represents the year 1864, as you would call it, or Year Minus Sixty-two, as we would call it. There was a man named Adam Rooney from Tennessee. In your world and ours. In your world, he was killed at age seventeen during the Civil War, gored while trying to crossbreed a bull and a Clydesdale. In our world, the man survived.”

The ranks of bugs on the wall changed colors again, turning shades of brown and tan and black, forming a rough portrait of an older man, smoking a pipe and looking out at the viewer through thick eyeglasses. He had a white Col o nel Sanders beard. “Mr. Rooney,” he continued, “was a genius. He went on to perform experiments with what he would call beastiology.”

“Yes,” John said. “People from our South are into that as well.”

The large man skipped a beat and continued, “This is the art of transforming naturally occurring life into forms that can be used by man to better the world. By 1881 Rooney had a self-shearing sheep and a species of snake that could harvest corn. By 1890 his group had an insectile flying machine. In 1902, or Year Minus Twenty-four in our terms, he created a primitive thinking machine from the brain of a pig.”

The image behind the man changed to a color depiction of several men standing over a vat of fluid. Inside it floated a twisted and deformed mass of what looked like brain tissue, about the size of a small dog. The men were wearing lab coats.

“I have studied your world for the last de cade, your language, your history. It is astonishing to me that you went to such unending lengths to build computation machines from metal and silicon switches when you have much more efficient versions inside your own skulls. Did this not occur to your scientists? By your year 1922, we had self-feeding, self-healing, self-growing and self-modifying computers, organic ones, that were approximately ten times as powerful as what you are using now in your world.”

The image shifted again, and this time a group of a dozen very proud-looking men were standing in front of a monster. The thing rose up behind them, no longer confined to a tank of fluid. It looked like a tree carved out of whale guts. It was a hideous twist of meat and fibers and strands that unspooled here and there like spiderweb. It stood as tall as a small tree, maybe twice as high as a man.

I got a dizzy spell, closed my eyes. A concussion? I clutched the kittens, one of them meowed. In just a few moments, I found I really did feel better.

“In 1926, or what we know as Year One, Mr. Rooney passed away. But something miraculous happened with the greatest of Mr. Rooney’s creations, the computation machine that had aided him with all of his other creations. On the very day Mr. Rooney passed, his creation became sentient.”

The large man gave a practiced pause in the middle of what I assumed was a prepared speech. This was where we were supposed to gasp in surprise, I guess. I nodded politely.

“It gave a name to itself,” said the large man, “and expressed desires and emotions. This was an astonishing surprise. This creation carried on Rooney’s work and conformed all of living nature to urge forth the advancement of mankind.”

Suddenly our vision was flooded with a view of an open, muddy field. The entire room had switched to a full-motion image, a panoramic view that made me dizzy. The image zoomed in on a long trench, like those used in World War I. The trench extended off in both directions and standing along the lip of the trench were men and women and children, lined up shoulder to shoulder. Some of the children were crying. Everyone was wearing clothes that were streaked brown and white and seemed to be made entirely of thin strips wrapped around and around their bodies. I thought for a moment that they were all wrapped in bacon.

The people seemed to obey an unheard command and all stepped down into the muddy trench. The children had to be dragged down against their will. Suddenly, puffs of dirt burst up from the ground around their bare feet and then the trench was filling with a dark flood. A close-in shot revealed the flood to be thousands and thousands of spiders, sharp bodies and yellow stripes. Bred for war.

There was a chorus of screams. The spiders swarmed over the victims, burrowing into skin and through ragged holes in muscle. I saw a spider burst out of one man’s eye, a half dozen tearing themselves out of holes in another man’s back, emerging from his gut and carry ing loops of intestine with them. Blood sprayed, limbs fell to the ground, bones were torn from legs and rib cages.

And then, the spiders were gone. The view lingered on the torn and bloodied victims and I realized that none had been killed. Instead, the spiders had left them in piles, hundreds and hundreds in a screaming, red, writhing mass, everyone missing limbs and baseball-sized chunks of flesh, men left blind and deaf and unable to move. No one came to their aid. The shot pulled back to reveal the trench stretched for miles in both directions, and the entire length now ran pink like a highway on a roadmap, the screams swelling up and up—

Then it was gone. The white room was back and the large man was standing before us, beaming with what I was pretty sure was pride. He said, “There are always those who resist progress.”

My eyes bounced around the room and I again had that suffocating feeling. No door. Hell, I couldn’t even point to the spot where the door had been. I looked over at John and he seemed to be trying to figure out if his chair could be used as a weapon. It looked rooted to the floor.

“Now,” said the large man, “knowing your world, this part may be a difficulty for you. Let me give you an example. In your world, as in mine, is it not considered bad to take and use, without permission, an object that another man is currently using or depending on?”

“Yes, in our world we call this ‘stealing,’ ” said John, with some impatience. “It is considered a greater crime, though, to unleash killer spiders on an unarmed crowd. We call that ‘arachnicide.’ ”

“But what if the object that you stole would later have injured or killed the man? Then stealing it would be saving his life. Or what if he had intended to use it as a weapon later, against an innocent person? And what if that weapon would have killed the child who would later grow up to cure a terrible disease?”

John, who had settled right into this conversation, scratched his chin, shrugged and said, “Well, you don’t know but you do the best you—”

“What if you could know,” said the large man. “You already, in your world, have machines that can compute and forecast outcomes and scenarios, that can look at air temperatures and wind patterns and predict the weather ahead of time. What if there was a thinking machine, an entity so powerful that it could foresee the outcome of any action? In it you would have the ultimate morality, the true ability to know which path was the correct one.”

I said, “Well, we have people in our world who believe in a . . .”

“I am not talking about a belief. What I am talking about exists here and now, in our world. It is something you can touch and see and smell. Something real.”

The lower half of his mask twisted and I thought he was smiling.

“Follow me.”

Mercifully, the door opened. I had the urge to knock the guy down and make a run for it, but where would we go? It was impossible to be farther from home than we were. Our home, in fact, literally did not exist at that moment. The large man led us back into the hallway, now empty of people. He led us to another stone doorway and when the door slid back we were greeted with a shaft, about as wide as the shaft for a big ser vice elevator. It led straight down, a row of lights vanishing into darkness hundreds of feet below.

Thin, black legs appeared over the edge, each as long as my body. I jumped back and heard a squeal as I stepped on a kitten, which was apparently following me. The large man put a calming hand on my shoulder.

The legs belonged to a spider.

A spider the size of a van.

It crawled up the opposite wall of the shaft, its mass neatly filling the entire space as if it were made for it. Its huge, bulbous back was facing us. A split formed in the spider’s body and it opened, revealing a rather clean interior that was a milky white. A light even blinked on in the cavity.

The large man walked inside the spider, there was room to stand up in there. He welcomed us inside and I decided on the spot that I wasn’t doing it, never, ever, ever. But John went in and then the dog and then the fluffy kittens, and at that point I didn’t really have a choice. I got inside the thing and the cavity closed and sealed us in. After a moment the spider jolted and we were riding down.

“Are you thinking what I’m thinking?” asked John.

“That if Franz Kafka were here his head would explode?”

“Actually, yeah.”

The large man, intent on continuing the tour, said, “We are on the verge of entering Year Seventy-seven of our new era, the era of guidance and enlightenment. We have made great strides. There is little that we need that we cannot extract from the very living energy that is the most powerful force the universe produces. Life is the energy that controls all other energies. Living man can split the atom and travel the stars and, soon, move from reality to reality. But it is life that is the engine at the center of all.”