“All passengers for London please disembark,” the sparkling AV pillars on the carriage ceiling announced. “This train will depart for Oslo in four minutes.”

The girls collected their big shoulder bags and hurried out onto the platform. They emerged into a long rectangular chamber, its ornately sculpted walls harking back to long-distant imperial grandeur. The line of twenty hatches connecting to the train appeared to be made of black wrought iron, Victorian-era space technology. On the opposite side, three large archways led to broad wave escalators that spiralled upwards with impressive curves.

Genevieve stayed close behind her big sister as she negotiated their way across the platform. At least this time they managed to avoid barging in to people. Excitement was powering a smile that would not fade.

An Earth arcology. London! Where we all came from originally. Home—sort of. How utterly utterly stupendous. It was the complete opposite of the nightmare that had been Norfolk by the time they left. This world had massive defences, and its people could do whatever they wanted with lots of fabulous machines to help them. She held Louise’s hand tightly as they stepped onto the wave elevator. “Where next?”

“Don’t know,” Louise said. For some reason she was completely calm. “Let’s see what’s up there, shall we?”

The wave escalator brought them onto the floor of a huge hemispherical cavern. It was like the arrivals hall of Mount Kenya station, only larger. The base of the wall was pierced by tunnel entrances radiating out to lift shafts and platforms for the local train network, while the floor was broken by concentric rows of wave elevators to the vac-trains. Bright informational spheres formed tightly packed streamers five metres above the heads of the thronging passengers, weaving around each other with serpentine grace. Right in the centre was a single flared spire of rock that rose up to eventually merge into the roof’s apex.

“It’s just another station,” Genevieve said in mild disappointment. “We’re still underground.”

“Looks like it.” Louise squinted up. Black flecks were zipping through the strata of informationals, as if they were suffering from static. She smiled, pointing. “Birds, look.”

Genevieve twirled round, following their erratic flight. There were all sorts, from pert brown sparrows to emerald and turquoise parrots.

“We’d better find a hotel, I suppose,” Louise said. She pulled her shoulder bag round to take the processor block out.

Genevieve tugged at her arm. “Oh please, Louise. Can’t we go up to the surface first? I just want to look. I’ll be good, I promise. Please?”

Louise tucked the shoulder bag back. “I wouldn’t mind a peek myself.” She studied the informationals, catching sight of one that seemed promising. “Come on.” She caught Gen’s hand. “This way.”

They took a lift up to the surface. It brought them out in a mock-Hellenic temple at the middle of a wide plaza full of statues and fenced in by huge oaks. A small commemorative plaque on a worn pillar marked the passing of the station’s old surface structures and iron rail tracks. Louise walked out from the shade of the temple, wandering aimlessly for a few yards until she simply stopped. It was as if the arcology was appearing in segments before her. Slowly. As soon as her mind acknowledged one part, another would flip up behind that, demanding recognition.

Though she didn’t know it, Kings Cross was the geographical heart of the tremendous Westminster Dome, which at thirty kilometres in diameter enclosed most of the original city, from Ealing in the west to Woolwich in the east. Ever since the first small protective domes went up over London (a meagre four km wide to start with—the best Twenty-first Century materials technology could manage), preservation orders had been slapped on every building of historical or architectural significance, which the conservationists basically defined as anything not built from concrete. By the time the Westminster Dome was constructed over that initial cluster of ageing weather shields, the outlying districts had undergone significant changes, but any Londoner from the mid Nineteenth Century onwards would have been able to find their way around the central portion without too much trouble. It was essentially one of the largest lived-in museums on the planet.

The nine smaller domes circling round outside the Westminster, however, were a different matter. London didn’t have the megatowers of New York, but the arcology still housed a quarter of a billion people beneath its geodesic crystal roofs. The outer domes were purpose built, four hundred square kilometres apiece of thoroughly modern arcology, with only tiny little zones of original buildings left as curios amid the gleaming condos, skyscrapers, and malls.

Louise wasn’t aware of them at all. She could see on the other side of the oaks that the plaza was encircled by a wide road jammed with sleek vehicles, all driving so close together you couldn’t walk between them. The vehicles merged in and out of the giant roundabout from wide streets that radiated away between the beautiful ancient grey-stone buildings surrounding the plaza. When she raised her gaze above the blue-slate roofs and their elaborate chimney stacks, she could see even grander and taller buildings behind them. Then beyond those . . . It was as though she was standing at the bottom of a mighty crater whose walls were made entirely from buildings. Around the plaza they were elegant and unique, with each one somehow merging cleanly into its neighbours to form compact refined streets; but they grew from that to plainer, larger skyscrapers, spaced further apart. The towers’ artistry came from the overall shape rather than detailed embellishments, moulded to suggest Gothic, Roman, Art Deco, and Alpine Bavarian influences among others.

And gathering all those disparate architectural siblings within its sheltering embrace was the external wall. A single redoubtable cliff of windows, a mosaic of panes so dense it blended into a seamless band of glass, blazing gold under the noonday sun. Out of that, rose the dome itself, an artificial sky of crystal.

Louise sat down heavily on the plaza’s stone slabs, and let out a whoosh of breath. Gen sat beside her, arms folded protectively round her shoulder bag. London’s pedestrians flowed round them, eyes consummately averted.

“It’s very big, isn’t it?” Gen said quietly.

“Certainly is.” All those buildings, so many people. Despite feeling light headed, a weight of worry was threatening to sink her again. How in heaven’s name am I going to find a single person amid this multitude? Especially when they probably don’t want to be found.

“Fletcher would really love this.”

Louise looked at her sister. “Yes. I think he would.”

“Do you suppose he’d recognize any of it?”

“There may be bits left over from his time. Some of these buildings look quite old. We’ll have to look it up in the local library memory.” She broke off and smiled. That’s it, everything you ever need to know is in the processor memories. Banneth will be listed somewhere, I just have to program in the right search. “Come on. Hotel first. Then we’ll get something to eat. How does that sound?”

“Jolly nice. What hotel are we going to?”

“Give me a moment.” She took her processor block out, and started querying the arcology’s general information centre. Category visitors, subsection residential. Central, and civilized. They’d wind up paying more for a classy hotel, but at least they’d be safe. Louise knew there were parts of Earth’s arcologies that were terribly crime-ridden. And besides, “Kavanaghs never stay anywhere that doesn’t have a four-star rating,” Daddy had said once.

Information slid down the screen. They didn’t seem to have star ratings here, so she just went by price. Central London hotels, apparently, cost as much to run as starships. At least the beds will be a lot more comfortable.