They passed five more sets of wheel tracks over the next couple of days as they continued across the continent.

     The first tracks they passed were running roughly from South West to North East, but as they continued west they angled more and more to the north, converging roughly on the position of New Philadelphia if you took the avoidance of difficult terrain into account.

     "I think we can be pretty certain now that the city still has people living in it," said Lungelo over the three way video link. His daughter was sitting beside him on the long sofa, looking healthy despite her close call with death. The only visible sign of it now was the bulge under the leg of her coverall where bandages covered her glued up injury. On the other half of the monitor screen, in another window, Philip nodded his agreement with Lungelo's words.

     "I think you're right," Andrew agreed. "It changes nothing, though. We have a mission to perform. We can't be distracted from it."

     "They deserve to be told that there are other survivors of the human race in the world, and that we're planning to return to the inner solar system. We cannot, in all conscience, withhold these facts from them."

     "And what if they react badly to the news?" Andrew replied. "They may consider us to be intruders into their territory. They may consider everything on this continent to belong to them, including the dysprosium. What if they try to stop us?"

     "Maybe they have a right to stop us," Lungelo said. "We came here thinking we were the last humans on the planet, thinking that everything belongs to us. We now know that that's not the case. Are we thieves? Are we going to steal from these people so that we can return to the sun and leave them marooned on this dead, frozen planet?"

     "The twelve cities renounced the idea of national territory," said Izindaba, leaning away from her father so she could look sideways at him. "They agreed that the full resources of the planet would belong equally to all of them."

     "She's right," Susan said to Lungelo. "They knew that, with the future of the human race so precarious, so dependent on everything working perfectly, the one thing that could doom us all would be conflict between the cities. The dysprosium belongs just as much to us as to the people of New Philadelphia. Its location is irrelevant."

     "That was two hundred years ago," Philip pointed out. "The descendants of those people may not feel the same way. We should at least try to contact them. Get their thoughts on the matter."

     "That would be foolish and dangerous," Andrew told him. "At the moment they have no idea we exist. We can go to LaSalle, get the dysprosium and go home again without them ever knowing we were here. The Council can contact them once we're safely home again."

     "Once we've gotten away with our I'll gotten gains," said Philip, frowning.

     "They're not ill gotten," Andrew replied. "As Izzy said, the dysprosium belongs just as much to us as it does to them."

     "You're talking legal," Philip told him. "I'm talking moral. We don't have to tell them why we're here. We just tell them we exist and that we want to be friends. A simple radio message."

     "Without a satellite, we'd have to be almost within visual range for them to receive a radio message," Andrew reminded him.

     "New Philadelphia is only a few hundred kilometres from LaSalle," Philip countered. "Once the dig is well underway, a rover could go there to make contact. We leave a bug to act as a relay. The rover can then withdraw to a safe distance, up to twenty klicks away. At no point would we tell them where we were or what we're looking for."

     "No," said Andrew flatly. "It's too dangerous. There's too much at stake for us to risk having a bunch of New Philadelphians turning up in force to stop us. As leader of this expedition, I forbid any attempt to contact them. When the mission's over we'll tell the Council everything we've learned and they can decide what to do, but until then we forget New Philadelphia exists. Understood?"

     Philip looked unhappy but he nodded. So did Lungelo, although it was clear that he also had reservations. Only Izindaba looked pleased by his decision and nodded happily, giving her father a triumphant look. Andrew guessed that they'd been talking about the issue for some time and would very probably continue to do so even though Andrew had made his ruling. Their faces disappeared from the monitor as they turned off their camera, and a moment later Philip's did so as well, leaving Andrew alone with his thoughts.

☆☆☆

     They arrived at LaSalle the next day.

     They were able to pinpoint their location using those buildings of the nuclear research facility that rose above the ice. The three gigantic containment vessels containing the nuclear reactors themselves were the most obvious structures, so layered in rippling, shimmering water ice that it was almost impossible to recognise them as man made structures. Beside them was the aircraft hanger sized building containing the turbines. Everything else was buried under the ice, including the six cooling towers that had once been the facility's largest, most recognisable structures. They had collapsed under the weight of the water ice that had built up on them during The Freeze, and the rubble had then been buried under ten metres of nitrogen and oxygen ice as the atmosphere itself had frozen to the surface of the planet.

     The map of the site they'd brought from New London told them where the research centre was located and the four rovers parked side by side on top of it. Andrew, Philip and Lungelo then put on their surface suits and went out to unpack the inflatable habitat from the cargo rover. They assembled aluminium spars and girders into a rectangular grid twenty metres across on the surface of the ice, then removed and unfolded the fork lift truck. Andrew used it to remove a three metre aluminium container from the wide hatch in the side of the cargo rover and place it in the middle of the grid.

     The others connected the power pack and the gas tanks to it with long tubes and cables. Philip turned it on and the sides of the container opened like a flower to reveal a compact cube of folded fabric. It expanded like rising dough as the gap between its inner and outer layers filled with helium gas and the habitat rose into a twenty metre hemisphere with six airlocks arranged symmetrically around the base. Each rover then reversed onto one of the airlocks and attached itself to it, leaving the remaining airlocks to allow the New Londoners to come and go from the unified structure thus formed.

     Heating elements warmed the inner layer of the habitat, and some of the heat leaked out through the base to warm the nitrogen ice and cause it to sublime into the vacuum. Soon, a gap of several centimetres had formed between the metal grid on which the habitat was sitting and the ice below, the vacuum insulating the base and allowing the interior of the habitat to warm up. They then shovelled ice from the surface in through the airlocks, where it vaporised to become breathable air.

     "Space to move around at last!" said Izindaba as she walked around on the tough, fuzzy floor of the habitat. She raised her arms and tossed her head to throw her long, dark hair around. "Those rovers get so cramped after a while."

     "You get used to it," Andrew replied. "I've lived in a rover so long that space like this almost makes me agoraphobic."

     "I assume we'll all still be sleeping in our rovers," said Halona. "This is just for work and recreation, right?"

     "Right," said Andrew distractedly. He was watching Jasmine and Joe, who had immediately paired off and were strolling hand in hand through one of the inner doorways to the section of the habitat that would become the laboratory. Once, he'd been happy with them being friends, with the prospect of their becoming more than friends. Joe was a good lad. Not quite as academically gifted as he would have wanted for his daughter, but he'd been willing to overlook that if he made her happy. Now though...

     "No-one is to go aboard someone else's rover," he said, raising his voice loudly enough to he heard by everyone. "And nobody goes near any of the vital equipment alone."

     "In case there's a remainer among us?" said Philip with a wry smile. "Just waiting for the chance to sabotage the mission?"

     "I trust each and every one of you," said Andrew, feeling a little foolish and embarrassed. "However, these are the guidelines set out by the Council and we will abide by them."

     "You're the boss," said Lungelo doubtfully, "but if we have to do everything in pairs that's going to slow down our work considerably. A lot of the equipment is designed to be used by one person. A lot of the time, the person with them will he just standing there doing nothing when they could be doing something useful."

     "And the person being watched is going to feel that they're not trusted," Halona added.

     "I'm sure we all understand that it's not one particular person who's not trusted," Susan replied. "It's just the situation we find ourselves in. And having someone there, watching you, means that, if something goes wrong, if some accident delays our work, the watcher can tell everyone that it wasn't deliberate sabotage." Andrew nodded gratefully at her.

     "Okay," said Philip with a cheerful grin. "So who's going to help me decorate? We've got a laboratory, a machine shop and a recreational space to create."

     "We'll all go," Andrew replied. "If we can get the habitat finished today, we can get to work properly tomorrow."

     He followed the other man back to the cargo rover, where they began removing the furniture and equipment carefully packed away inside.

☆☆☆

     "When we were planning this mission," said Andrew a couple of hours later, "we didn't think we'd have to hide from potentially hostile locals."

     He and Philip, wearing surface suits, were standing a hundred metres away from the habitat, looking down on it from a wide, low hump that the map said covered LaSalle's administration block. From there, the habitat and the rovers arranged around it were brightly lit by the half dozen clusters of filament lamps arranged at the tops of tall poles. It made the surrounding terrain look dark in comparison even though it was noon, with the distant sun almost directly overhead.

     "New Philly is to the south of us," Philip replied. "The turbine building is between it and us, and there are hills and ridges beyond in all directions. A rover would have to he almost on top of us before it saw the lights. I don't think we're advertising our presence. The tracks left by our rovers is a bigger danger. If a New Philly rover comes across them, they'll lead them straight here."

     Andrew nodded. "Do you still think I'm foolish to be afraid of them?" he asked.

     "You're not foolish and you're not afraid of them. You're cautious. You may be taking caution to an unnecessary extreme but that's better than erring in the other direction. I've had a chance to think since we had our last conversation and I now think you were right to overrule me. The United States used to be a good, civilised country, but that was two hundred years ago. Who knows that they are now?" He looked up into the sky where a small constellation of stars was passing by. The space station and its retinue of half finished spaceships. "All they have to do is look up to know that someone else survived elsewhere on the planet," he continued. "And they've made no attempt to contact us. All they had to to was shine a bright enough light up into the sky and the astronauts would have seen it. For some reason they chose not to do so."

     Andrew nodded, feeling relieved. Being at odds with the larger, physically intimidating man made him nervous. He was greatly relieved that he'd come around to his way of thinking.

     "That means the guys up there can see our lights," he said, staring up at the space station. "They know we made it this far. Most of us at least."

     "The next time a ground survey satellites passes overhead they'll see that we've only got four rovers," Philip agreed. "They'll know we suffered losses. You know, we could probably communicate with them, if we had to. We could shine a light up at them. Dots and dashes, morse code. They can signal back by reflecting sunlight back down at us."

     "The space station only passes over the same spot on Earth every six weeks," said Andrew with a smile. "The next time they pass over we'll be ready to head back, if everything's gone well. If there's anything we want to say to them, we'll have about five minutes to say it before they go below the horizon."

     "Like you said," said Philip, "the most important thing we can tell them, they already know. That most of us made it, and that some didn't. They'll pass the news on to New London and then wait for us to head back on our own."

     "Which means we're still on our own," said Andrew. "Just the eleven of us, with no backup to call upon and potentially hostile natives. I'm scared, Phil, and I'm not afraid to admit it."

     Philip nodded, and the two men watched the small cluster of stars as it dropped towards the horizon and eventually passed out of sight.