After a while, Jasmine entered the cockpit to replace James and Andrew. The autopilot was perfectly capable of driving the rover through the night over unmapped terrain, having a complete set of pre-programmed procedures to guide it through any unexpected situation it might encounter, but Andrew felt happier having a member of his family actually there, keeping an eye on things. Just in case. It meant that it wasn't possible for the entire family to be in the recreation room at once while the rover was moving, but the rest of the family was willing to indulge him in this, just for his peace of mind.

     When Andrew and James walked in, David and Susan were sprawled on either end of the sofa, sharing a bag of snacks while they watched an old movie on the monitor screen on the wall opposite them. Andrew groaned inwardly when he recognised it. They lived in a dangerous world now in which a knowledge of science was essential for survival. That had been true when the movie had been made, twenty years before, and yet the movie contained some atrocious science.

     Susan heard his groan and looked round at him. "Now don't start again," she warned. "It's got a good story. I loved this movie when I was a little girl."

     David looked round at him as well. "Don't you like it, Dad?" he asked.

    "Is this the one where the guy has to cross a lake of liquid nitrogen," said Andrew as he went across to one of the room's armchairs. "Using floating slabs of nitrogen ice as stepping stones?"

     David looked around with a guilty smile. "I like it!" he protested. "It's good."

     "Nobody making the movie knew that nitrogen ice sinks in liquid nitrogen?"

     "The priority back then was to keep people entertained, not to educate them," said Susan. "Remember how things were back then. The fall of New Richmond and New Beijing was still fresh on everyone's mind. Everyone was afraid that New London would suffer the same fate, that the last bastion of humanity would be extinguished. Even if we survived, the entire human race was now trapped in a single underground city. It was vital to keep the population entertained, to keep them from lapsing into cabin fever. A massive, collective madness that would have destroyed everything."

     Andrew nodded, knowing the truth of it. The Governing Council had encouraged the making of music, movies and television series, with rewards of extra food rations and other luxuries for anyone who created a work of art, no matter how bad the quality. What had mattered was that fifty thousand trapped human beings always had something new to talk about, to take their minds off the fact that freedom, the ability to leave the city, was still years away.

     "I know that," said Andrew. "And you'll have noticed there are dozens and dozens of movies on the same theme. People forced, for one reason or another, to go out onto the surface where everyone dies horribly except for one person who makes it back alive to the warmth and safety of the city."

     Susan chuckled. "Propaganda about as subtle as a mallet to the head," she agreed. "The surface is dangerous. Stay in the city, where it's safe."

   "You can do that while being scientifically accurate. God knows there're enough real dangers out here."

     "Well, it is educational," said Susan. "When I was in school, my physics teacher told us to watch the movie and then write an essay on all the scientific inaccuracies it contained."

       "It's a great movie!" David protested. "There's loads of action in it. Lots of explosions."

     "And lots of people talking to each other, out on the surface, without helmets on."

     "In a movie, you've got to be able to see the actor's faces," pointed out Susan. "What's the point in it being a Tom Falcon movie if you can't see it's Tom Falcon? God, I had such a crush on him when I was a teenager." She saw the expression on Andrew's face and burst out in laughter. "I was a teenager!" she said. "And besides, Tom Falcon must be about fifty by now."

     Andrew decided it would be undignified to make any reply to that so he went to the kitchen area and took a packet of cottage pie from the storage canister. He pulled it open, added water and put in in the microwave oven. "James, have you eaten yet?"

     "I'll have some beef later," his son replied from the armchair in the other corner of the room. "I'm not hungry yet."

     "What about you others?" asked Andrew.

     "We ate with Jasmine," Susan replied. "We had turkey. I'm not that fond of beef."

     "It's the same stuff," pointed out David. "Just different flavours and textures."

     "She knows that, buttface," James replied. "She's been eating it longer than you."

     "No name calling please," said Andrew. The microwave beeped and he took out the hot packet of algal paste textured and flavoured to resemble cottage pie. As he took it back to his armchair it occurred to him that it had been two hundred years since anyone had eaten a real cottage pie. It had been two hundred years since anyone had eaten real beef or real turkey or real Italian food. What were the chances that the meal he was about to eat bore any resemblance to the ancient meal it was named after? What had real turkey tasted like? He dismissed the thought as irrelevant. The food they ate now tasted good. It was hot and satisfying and came in endless varieties. Those with culinary tendencies could buy simple ingredients and make their own foods according to complicated recipes that they spent years perfecting. Yet another way for those back in the city to entertain themselves as they tried to forget that their entire world consisted on walls, floors and ceilings.

     He dug into the cottage pie with his fork and lifted the steaming brown paste to his mouth, but before he could eat it the movie disappeared from the screen to be replaced by the face of Phil Badger. "Ah, Andy, you're there," he said. "Where are you right now?"

     "Just east of Bassenthwaite Planitia," Andrew replied, putting the ceramic bowl on a sideboard beside a dangling spider plant. "I told Ben about our problems crossing the glacier."

     Philip nodded. "Listen, we need you to take a little trip further east. There's been an incident here at the dig site."

     Andrew sat up straight, suddenly alarmed. "What kind of incident?"

     "Reg stole all the dysprosium," said Philip. "He disabled the other two rovers, then took off in the one we'd loaded all the dysprosium in. He also disabled all our transmitters. We've only just managed to get one of them working again, but the rovers aren't going anywhere without spare parts from the city. We need you to go after him and get our dysprosium back."

     "He's a Remainer?" said Andrew. "But he was the one most enthusiastic about the Return!"

     "Just an act, it seems. To hide his real feelings."

     "Was anyone hurt?"

     "Not really. My son disturbed him sabotaging our rover. Reg tied him up and gagged him. He's okay, just a bruised ego, but I'm going to have a few things to say to the bastard when I get my hands on him."

     "Thank God," said Andrew with heartfelt relief. Joe could be a bit strange at times, but Jasmine was fond of him. She would be devastated if anything happened to him.

     "He's heading east towards Thirlmere. That was five hours ago. He'll have passed Thirlmere by now, and we assume he's still heading east. If you keep heading south, you should be able to pick up his trail within a couple of hours."

     Andrew nodded. "We'll do our best," he said. "But why would he do this? What's he going to do with five tons of dysprosium? It's an element, you can't destroy it. He can't just dump it somewhere on the surface. His wheel tracks'll lead us straight to it. Not matter what he does with it, it's only a matter of time before we get it back."

     "He must have a plan to keep it out of our hands permanently, but we have no idea what it might be. We assume his first priority is to get as far away as possible from New London before they send more rovers out after him. At the moment you're the closest rover to him. You're the only one who has a chance to catch up with him before he gets too far away."

     Andrew nodded again, but there was a deep, worried frown on his face. "We thought we knew him," he said. "It seems we didn't. Do you think he's dangerous?"

     "Well, he could have hurt my son and he didn't. He seems to have taken care not to hurt anyone so far."

     "Because he could accomplish his aims without having to," said Andrew. "Who knows what he might do if he thinks he's got no choice, though. It seems we have no idea who he really is or what he's capable of."

     "That's true, I suppose," said Philip. "Yes."

     "And the thing is, I've got my whole family here, with me. I don't want to take them into danger."

     Phil frowned and looked thoughtful. "I understand how you feel," he said. "I'll talk to Bill and see if we can work something out. Until then, will you see if you can pick up his trail? You don't have to engage him or anything. Just find him and follow him. See where he goes."

     Andrew nodded reluctantly. "You'll talk to Bill?"

     "I will. I promise."

     "Maybe I should talk to him too."

     "By all means. We'll work something out, I promise. I would never ask you to put your family in harms way."

     Andrew turned to Susan. "You okay with that?" he asked.

     She was unhappy with the whole idea, the expression on her face left no doubt about that. Her husband was an engineer, not a lawman. He had no business putting his life in danger getting involved with a potentially dangerous saboteur. She couldn't say that in front of Philip, though. She loved Andrew too much to make him look like a timid coward in front of his friend and co-worker. Instead, she would be trying to think of some logical, practical reason why they couldn't do what Philip was asking them to do. Something that would allow them to avoid causing offence to Philip and embarrassment to Andrew by simply saying no.

     "All he's asking is to trail him," said Andrew reassuringly. "He's not asking us to stop him all by ourselves. Just track him. Keep him pinpointed so someone else can take him into custody." He turned back to the screen. "Right?"

     "Right," Philip replied. "Just follow. Don't engage."

     "We only have enough food on board for another five days," said Susan. "We were going to restock the next time a cargo rover arrived at the dig site. We can't undertake a long pursuit."

     "That's right," said Andrew. "We can make it back to the dig site, but longer treks are out of the question. We'd need to be reapplied. Perhaps there's a life hutch somewhere ahead of us we can raid."

     "We might be able to send a sub-orbital supply rocket to land somewhere along your path," said Philip. "With this much at stake, I'm pretty sure I'll be able to talk Bill into it."

     "If they can resupply us," said Andrew to Susan, "would you be okay with that? Setting out into the unknown? Reg'll probably be heading well outside explored territory. Beyond the furthest life hutches."

     Susan struggled to think of another reason why he couldn't do it, but nothing occurred to her. "If you think we can do it without putting the children in danger," his wife replied. "We don't put the children at risk. That's a deal breaker. I trust the rover. Even if we get stuck in a crevasse somewhere, it'll keep us alive until a rescue rover can get to us. Reginald is what worries me. What might happen if we catch up with him. I don't want to do that with the kids aboard."

     "So you'd be okay with it if we can take your children off your hands?" said Phil hopefully.

     "We'd both be a lot happier if that could happen," said Andrew.

     "Okay," said Philip. "I'll talk to Bill and see what we can work out."

     "Thanks, Phil," said Andrew. "I'll get up to the cockpit and work out our best course."

     "Appreciate it, Andy."

     "No worries."

     Phil Badger's face disappeared from the screen and the movie resumed, but no-one was watching it any longer. "I can come with you," said James. "Help you find Reg."

     "No, I need you to look after the others," said Andrew. "You're the man of the house until I get back."

     "Don't patronise me, Dad."

     Andrew smiled ruefully. "Sorry," he said. "But I'll be a lot easier in my mind knowing that the rest of you are safe. I know that you're just as capable on the surface as I am but it's Reg that worries me. Nature is predictable. It follows rules, but there's no telling what this man might do if he's cornered."

     "And what about us?" asked Susan. "Are we supposed to be happy with you going into danger like that?"

     "There's no choice, you heard what Phil said."

     "He always seemed so nice," said David. "We used to talk about the old days. Before The Freeze. How people used to live back then."

     Andrew nodded thoughtfully. Reginald Fox had been a historian. He knew how the world had been better than almost anyone else. Who knew what obscure bit of knowledge he was planning to use to put the dysprosium permanently out of their reach? Maybe something nobody else would ever have thought of. "Was there anything in particular he liked to talk about?" he asked.

     "Mythology," said David. "Especially Greek and Roman mythology. He was always going on about the ancient Gods and monsters like Zeus, Poseidon, Typhon, Hephaestos. That sort of thing. He could talk about them all day."

     Andrew nodded with disappointment, not seeing any connection with something that Reginald Fox might be able to put to use. "Well, better get forward and tell Jasmine the good news, I suppose," he said, his cottage pie forgotten as he made his way towards the cockpit.