At the time Louise Ye Armonk was well established in her chosen field of GUTship engineering… at least, as established as any mere fifty-year-old could be, in a society increasingly dominated by the AS-preserved giants of the recent past. Louise had even worked, briefly, with Michael Poole himself.

Why had Poole’s wormhole time link been built? There were endless justifications — what power could a glimpse of the future afford? — but the truth was, Louise knew, that it had been built for little more than the sheer joy of it.

The Interface project came at the end of centuries of expansion for mankind. The Solar System had been opened up, first by GUTdrive vessels and later by wormhole links, and the first GUTdrive starship fuelling port — Port Sol — was already operational.

It was difficult now to recapture the mood of those times, Louise thought. Confidence — arrogance… The anthropic theories of cosmological evolution were somewhere near their paradigmatic peak. Some people believed humans were alone in the Universe. Others even believed the Universe had been designed, by some offstage agency, with the sole object of delivering and supporting humans. Given time, humans would do anything, go anywhere, achieve whatever they liked.

But Poole’s Interface had been a bridge to the real future.

The incident that followed the opening of the wormhole had been confused, chaotic, difficult to disentangle. But it had been a war — brief, spectacular, like no battle fought in Solar space before or since, but a war nevertheless.

Future Earth — at the other end of Poole’s time bridge, a millennium and a half hence — would be under occupation, by an alien species about whom nothing was known save their name: Qax.

Rebel humans from the occupation era were pursued back through time, through Poole’s Interface, by two immense Qax warships. The rebels, with the help of Michael Poole, had destroyed the warships. Then Poole had driven a captured warship into the Interface wormhole, to seal it against further invasion — and in the process Poole himself was lost in time. The rebels, stranded in their past, had fled the Solar System in a captured GUTdrive ship, evidently intending to use time dilation effects to erode away the years back to their own era.

The System, stunned, slowly recovered.

Various bodies — like the Holy Superet Light Church — still, after a hundred and fifty years, combed through the fragments of data from the Interface incident, trying to answer the unanswerable.

Like: what had truly happened to Michael Poole?

It was known that the Qax occupation itself would eventually be lifted, and humanity would resume its expansion — but now more warily, and into a Universe known to be populated by hostile competitors…

A Universe containing, above all, the Xeelee. And it was said that before Poole’s wormhole path to the future finally closed, some information had been obtained on the far future — of millions of years hence, far beyond the era of the Qax. Louise could see how some such data could be obtained — by the flux of high-energy particles from the mouth of the collapsing wormhole, for instance.

And the rumors said that the far future — and what it held for mankind — were bleak indeed.

Louise and Mark stood on the forecastle deck and looked up toward the Sun.

The Great Northern, Louise’s GUTdrive starship, passed serenely over their heads, following its stately, four-hour orbit through the Kuiper object’s shallow gravitational well. The Northern’s three-mile-long spine, encrusted with sensors, looked as if it had been carved from glass. The GUTdrive was embedded in a block of Port Sol ice, a silvery, irregular mass at one end of the spine. The lifedome — itself a mile across — was a skull of glass, fixed to the spine’s other end. Lights shone from the lifedome, green and blue; the dome looked like a bowlful of Earth, here on the rim of the System.

“It’s beautiful,” Mark said. “Like a Virtual. It’s hard to believe it’s real.” The light from the Britain’s dome under-lit his face, throwing the fine lines around his mouth into relief. “And it’s a good name, Louise. Great Northern. Your starship will head out where every direction is north — away from the Sun.”

Staring up at the shimmering Northern now, Louise remembered Virtual journeys through ghostly, stillborn craft: craft which had evolved around her as the design software responded to her thoughts. How Brunel would have thrived with modern software, which once again enabled the vision of individuals to dominate such huge engineering projects. And some of those lost ships had been far more elegant and daring than the final design — which had been, as ever, a compromise between vision and economics.

…And that was the trouble. The real thing was always a disappointment.

“Louise, you shouldn’t fear the future,” Mark said.

Instantly Louise was irritated. “I don’t fear it,” she said. “Lethe, don’t you even understand that? It’s Michael Poole and his damn Interface incident. I don’t fear the future. The trouble is, I know it.”

“We all do, Louise,” Mark said, his patience starting to sound a little strained. “And most of us don’t let it affect us — ”

“Oh, really. Look at yourself, Mark. What about your hair, for instance? — or rather, your lack of it.”

Mark ran a self-conscious hand up and over his scalp.

She went on, “Everyone knows that this modern passion for baldness comes from those weird human rebels from the future, the Friends of Wigner. So you can’t tell me you’re not influenced by knowing what’s to come. Your very hairstyle is a statement of — ”

“All right,” he snapped. “All right, you’ve made your point. You never know when to shut up, do you? But, Louise — the difference is we aren’t all obsessed by the future. Unlike you.”

He walked away from her, his gait stiff with annoyance.

They climbed down into the engine room. Multicolored light filtered down through an immense skylight. Four inclined cylinders thrust up from the floor of the ship; the pistons stood idle like the limbs of iron giants, and a vast chain girdled the drive machinery.

Louise rubbed her chin and stared at the machinery. “Obsessed? Mark, the future contains the Xeelee — godlike entities so aloof from us that we may never understand what they are trying to achieve — and with technology, with engineering, like magic. They have a hyperdrive.” She let her voice soften. “Do you understand what that means? It means that somewhere in the Universe, now, the damn Xeelee are riding around in FTL chariots which make my poor Northern look like a horse-drawn cart.

“And we believe they have an intraSystem engine — their so-called discontinuity drive — which powers night-dark ships with wings like sycamore leaves, hundreds of miles wide…

“I’m not denying my GUTdrive module is a beautiful piece of engineering. I’m proud of it. But compared to what we understand of Xeelee technology, Mark, it’s — it’s a damn steam engine. Why, we even use ice as reaction mass. Think of that! What’s the point of building something which I know is outdated before I even start?”

Mark laid a hand on her shoulder and squeezed. His touch was warm, firm, and as he’d no doubt intended — disconcertingly intimate. “So that’s why you’re running away.”

“I’d hardly call leaving on a one-way colonizing expedition to Tau Ceti ‘running away’.”

“Of course it is. Here is where you can achieve things — here, with the resources of a Solar System. You’re an engineer, damn it. What will you build on some planet of Tau Ceti? A real steam engine, maybe.”

“But — ” She struggled to find words that didn’t sound, even to her, like self justifying whines. “But maybe that would count for more, in the greater scheme of things, even than a dozen bigger and better Northerns. Do you see?”