Coypu’s newest invention did not look like very much at all. Just a lot of boxes, wires and assorted gadgetry spread all over the room. But he was proud of it.

“Still in rough shape, as you can see,” he said. “Breadboarded components. I call it my parallelilizer…”

“I would hate to say that three times fast.”

“Don’t joke, diGriz! This invention will change the fate of the known universe and at least one unknown one.”

“Don’t be so touchy,” I said soothingly. “Your genius will not go unmarked, Prof. Now, would you be so kind as to demonstrate how your parallelilizer works.”

Coypu sniffed and muttered to himself while he made adjustments on the machine, threw switches and tapped dials. The usual thing. While he was busy I was busy too giving Angelina a quick hug and she hugged right back. The professor, wrapped up in his work, never noticed that we were wrapped up in ours. He lectured away while we snogged.

“Precision, that is the important thing. The various parallel universes are separated only by the probability factor which is very thin as you can well imagine. To pick just one probability out of all the countless possible ones is the trickiest part of the operation. Of course the probabilities that vary the least from ours are the closest, while completely changed probability universes are the most distant and require the most power. So for this demonstration I will take the nearest one and open the portal to it, so!”

A last switch was thrown and the lights dimmed as the machine sucked in all the available power. On all sides machines hummed and sparkled and the sharp smell of ozone filled the air. I let go of Angelina and looked around carefully.

“You know, Professor,” I said. “As far as I can see absolutely nothing has happened.”

“You are a cretin! Look, there, through the field generator.”

I looked at the big metal frame that was wrapped with copper wire and glowing warmly. I could still see nothing and I told Coypu so. He screeched in anger and tied to pull out some of his hair, failing in this since he was almost bald.

“Look through the field and you see the parallel universe on the other side.”

“All I can see is the lab.”

“Moron. That is not this laboratory, but the one on the other world. It exists there just as it does here.”

“Wonderful,” I said, smiling, not wanting to offend the old boy. Though I really thought he was crackers. “You mean if I wanted to I could just step through the screen and be in the other world?”

“Possibly. But you might also be dead. So far I have not attempted to pass living matter through the screen.”

“Isn’t it time you tried?” Angelina asked, clutching my arm. “Only with some living matter other than my husband.”

Still muttering, Coypu exited and returned with a white mouse. Then he put the mouse in a clamp, fixed the clamp to a rod, then slowly pushed the mouse through the screen. Absolutely nothing appeared to happen other than that the wriggling mouse managed to squirm out of the clamp and drop to the floor. It scuttled aside and vanished.

“Where did it go?’“ I asked, blinking rapidly.

“It is in the parallel world, as I explained.”

“The poor thing looked frightened,” Angelina said. “But it didn’t appear to be hurt in any way.”

“Tests will have to be made,” Coypu said. “More mice, microscopic examinations of tissue, spectroscopic determination of factors…”

“Normally yes, Prof,” I said. “But this is war and we just don’t have the time. There is one real time saver that will enable us to find out right now—”

“No!” Angelina called out, being faster on the uptake than the professor. But she said it too late. Because even as she called out I was stepping through the screen.

The only sensation I felt was sort of a mild tingle, though even this might have just been a product of my fevered imagination since I was expecting to feel something. I looked around and everything looked very much the same to me—though of course all of the parallelilizer equipment was missing.

“Jim diGriz, you come back at once or I’ll come after you,” Angeline said.

“In just a moment. This is a momentous instant in the history of science and I want to experience it fully.”

It was disconcerting to look back through the screen and find that the view of the other lab—as well as Angelina and the professor—vanished when I walked off to one side. From the front the field itself was invisible, though when I walked around behind it it was clearly visible as a black surface apparently floating in space. Out of the corner of my eye I saw something move; the mouse scuttling behind a cabinet. I hoped that he liked it here. Before returning I felt I had to mark the important moment some way. So I took out my stylus and wrote SLIPPERY JIM WAS HERE on the wall. Let them make of that what they will. At that moment the door started to open and I instantly nipped back through the screen. I had no desire to meet whoever was coming in. It might even be a parallel-world duplicate of me, which would be disconcerting.

“Very interesting,” I said. Angelina hugged me and Coypu turned off his machine. “How big can you make the screen?” I asked.

“There is no physical or theoretical limit on its size since it doesn’t exist. Now I am using metal coils to contain the field, but they are dispensable in theory. Once I am able to project the field without material containment it will be big enough to send the entire alien fleet through.”

“My thought exactly, Professor. So, back to your drawing board and get cracking. Meanwhile I’ll break the news to our masters.”

Calling together all of the chiefs of staff was not easy since they were deeply involved in running the war, if not in winning it. In the end I had to work through Inskipp who used the powers of the Special Corps to call the meeting. Since they were using this base as headquarters for defense they found it hard to ignore the call of their landlord. I was waiting when they arrived, crisp and shining in a new uniform, a number of real medals, and a few fakes, pinned to my chest. They grumbled to each other, lit large cigars and scowled in my direction. As soon as they were all seated I rapped for attention.

“Gentlemen, at the present time we are losing the war.”

“We didn’t have to come here to have you tell us that,” Inskipp snarled. “What’s up, diGriz?”

“I brought you here to tell you that the end of the war is now in sight. We win.”

That caught their notice, all right. Every grizzled head was now leaning in my direction, every yellowed or drooping eye fixed upon me.

“This will be accomplished through the use of a new device called the parallelilizer. With its aid the enemy fleet will fly into a parallel universe and we will never see them again.”

“What is this madman talking about?” an admiral grumbled.

“I am talking about a concept so novel that even my imaginative mind has difficulty grasping it, and I expect that your fossilized ones can’t understand it at all. But try.” A deep growl ran through the room with that, but at least I had their attention now. “The theory goes like this. We can time travel to the past, but we cannot change the past. Since we obviously make changes by going into the past, those changes are already part of the past of the present we are living in.” A number of eyes turned glassy at this but I pressed on. “However if major changes are made in the past we end up with a different past for a different present. One we don’t know about since we are not living in it, but one that is real for the people who do exist there. These alternate time lines, or parallel universes, were inaccessible until the invention of the parallelilizer by our Corps genius, Professor Coypu. This device enables us to step into other parallel universes, or to fly in or get there in a number of interesting ways. The most interesting will be the generation of a screen big enough for the entire alien fleet to fly through so they will never bother us again. Any questions?”