"Maybe not on this occasion," she said, taken down a notch. "You don't want us suited up for this excursion, do you?"

"I'm going to show you the emergency isolation facility we've set up here, for what it's worth. And where we've hidden the case."

Ryder looked forward to this little tour. He knew aspects of it unnerved those unused to grubbing around in a dark, subterranean world. He and Brian had set up a string of lights powered by a small hydro-generator embedded in a nearby mountain stream. Not enough to read by, but enough light to know when to duck or step around bottomless pits. Augmented by their head torches, the dim lights allowed the three to stow the suits in waterproof bags near the entrance.

"Hey, Jena, let me go first," shouted Ryder, as she darted like a rabbit into its hole. She let him catch up.

"I thought you were going to do that typically English tour where you led from behind," she said. "What kept you?"

"I had to relock the gate behind us."

"Impressive," Dan said. "Do we need to watch our heads?"

"Absolutely. It goes in more or less horizontal, but the miners must have been only five feet tall a couple of centuries ago, so watch the ceiling, the floor and the walls. There are rusty iron brackets waiting to catch your head. Follow me."

Thirty minutes later, they'd reached a gap in the left wall.

"We are going into a small gallery on your left," Ryder said. "There's a small step but it means the floor is dry. Here we are."

Contrary to the low tunnel on the way in, this room had at least a twenty-foot headroom. The extra volume allowed other senses to taste the air. A slight musty smell from bat droppings and the ever-present dampness took the edge off considering the mine as a holiday destination.

"Cosy," said Jena. "A home from home. Hey, cute armchair and, my God, beds. Is this your secret love nest, Ryder?"

"I guess this is a kind of isolation dormitory in case anyone gets infected," Dan said. "Excellent, Ryder. You have a heater, fridge, water filter, first aid..."

"Hey, now this is luxury," Jena said. "A computer! For playing games?"

"Why not?" Ryder said. "They'll need to pass the time."

Jena wore a look of disgust. "Give them a pack of cards. What a waste of a resource."

"Am I right in thinking it's networked to the centre?" Dan said. "So it can be used for communication? Cell phones won't work this deep in the mountain. This webcam works too? Of course it would and the medical sensors. You've thought of everything. Cool, huh, Jena?"

"Got you," said Ryder to Jena, who had stood with folded arms while the two men's voices echoed.

"Fancy thinking it was for games," Dan said and then laughed with Ryder.

"Shut up. Shaddup! You'll have the whole goddamn mountain shaking to bits," she cried then laughed too.

"It's not finished and so far not needed. Both of you come over here and give me your head torches." Ryder led them to the centre of the room. After a moment, the lights went out. If Ryder was expecting a scream, a shout, even a gasp in the complete pitch blackness, he had to be disappointed.

"Cool."

Dan said, "Astronaut training is pretty tough, Ryder."

After a minute, Ryder said, "Few people experience total blackness in their lives. Outside at night, with no mains electricity, a moonless overcast sky will still have a glimmer of light from the odd lamp. Of course, we don't see complete blackness. There are often floaters or something stimulating the optic nerve, making us see spots. Yes?"

"Can't say I do. How about you, Jena?"

"Nope."

"Must be because I'm older than you two, I suppose," Ryder said, putting the lights back on, and then he saw their smiles. "Touche, bastards."

When the laughter reverberated away, Jena looked under a tarpaulin. "Where have you hidden our luggage, Ryder?"

"This way." Ryder returned to the gallery. He couldn't resist looking back down the thousand metres to the mine entrance. A fingernail of bright light. A sight that gave him both inexplicable elation and a tinge of entrapment.

After another hundred metres walking and fending off an increasing frequency of jutting rocks, he stopped and looked back once more. He could no longer see the mine entrance. There must have been enough of a kink to deny him the exit light.

"Careful here," Ryder said, with Dan and Jena on either side. At their feet was a sharp edge to a deep pit stretching side to side and ten metres in front. Light bulbs lit down and up, casting shadows between illuminated rock segments.

"Wow," exclaimed Jena. "It looks like a bottomless pit. This is beautiful, Ryder."

"It sure is," Dan said. "Takes your breath away, the soft yellow mixed with cold greys and spooky shadows. People would pay to see this. Amazing. I take it this is where the tour ends. I can't see an easy way round."

"We have to get across," Ryder said. "Because the case is in a cavern on the other side."

"A hidden bridge?" Jena said.

"Watch and be amazed," Ryder said. "It's surprisingly easy to jump."

"No way. You'll kill yourself. And I'm only just getting to like you."

He laughed, took a few steps back, ran to the brink, and jumped. He landed in the pit, but it was an illusion. An inch of water. The pit was a perfect reflection in a shallow pool of undisturbed water.

The two astronauts, after their initial shock, laughed and then jumped too, splashing like children at the seaside.

Across the pool, they rounded a bend to an end cavern. It had similar equipment to the isolation room, with the addition of a padlocked steel cage. Although used by miners to store their more valuable tools, it served the new owners as a safe. The padded container looked no different than when they enclosed the case with it out in orbit. A light and a camera looked at it from high up on the wall. Ryder waved and thumbed up at the camera.

"Derek is monitoring it, especially since we would have triggered a couple of motion-sensor alarms since entering the mine."

The three stood looking at the wrapped case.

Dan started. "We didn't get round to discussing what to do with this beastie."

"I know what we should do with it," Jena said. "Throw away the key to that padlock."

Ryder dragged over a couple of wooden chairs to add to the one facing the case's prison. They all sat while Ryder extracted a flask of hot coffee and Bronwyn-made biscuits from his rucksack. They munched and sipped in quiet contemplation.

"It needs to be opened and soon," Dan said.

"I agree," said Ryder. "It could be mankind's salvation."

"Or its end," Jena said.

Ryder said, "Certainly humans are going to be wiped out in a year or so at the present rate. People have dropped like flies with the lack of medication to overcome their pre-ARIA conditions and post-ARIA epidemics. Soon, there'll be none who can read or remember basic skills."

Jena offered a wry smile. "They'll still be able to make babies."

"Yes, instinct and hormones will see to that," Dan said. "But ARIA means the day after, they'll forget they've had a baby, or where it is. They'll wonder why they're sore, look for a reason and, with luck, find a baby in a cot. How many babies will starve to death within days? Or fall prey to the packs of dogs we've heard about?"

"That's sure worse than when humans dropped out of the trees," Jena said.

"Yes," said Ryder. "Those early humans were able to remember what they learned."

"If it's just down to us uninfected humans to regenerate the race," said Jena, edging her chair closer to Ryder. "We'd better get started right away."

"Umm," Ryder said, "you have a point. Are you ready to be a baby factory?"

"Oh my God, I hadn't thought this one through." Jena edged her chair equidistant from both men.

Dan added to her angst. "Of uninfected people, we only know of this group in North Wales and Charlotte, on her own in Australia. How many is that?"

"Fourteen altogether," Ryder said. "According to the biologists here, that is too small a base for a sustainable population regeneration since only four women here are of child-bearing age. I'm afraid I don't fancy driving all the way to Australia to get Charlotte pregnant."

"We could store eggs from the women before we make them pregnant," said Dan. "Then use our sperm and cloning technology to set up a kinda human embryo factory to impregnate the four women with, say, six at a time."

Ryder, sneaked Dan a sly wink. "Then the women would have to be more or less permanently pregnant with sextuplets."

"Who would look after all the infants?" Jena was aghast.

"You women, of course," Ryder said. "We'd be needed doing other physical work. Women are the natural child rearers. Of course all this might be unnecessary if, somehow, ARIA could be reversed or at least stopped in time."

"Could be worthwhile seeing what's in this case, then," Dan said, winking at Ryder.

"You fuckers," Jena said. "All this baby-factory stuff was just a ploy to get me to agree to opening the case. As if you needed my blessing."

THEIR RETURN TO THE CENTRE CORRESPONDED WITH LUNCHTIME. Teresa's perimeter tour group entered just as the other two groups finished their soup. Ryder looked up to see Teresa, who had linked arms with Antonio. Her face bright and smiling more than he'd seen for a long time. He fought his immediate urge to run out and pile into Antonio. If he wasn't going to hang on to Teresa, it was because he and she weren't right for each other. The fact that they had not considered getting married put strength to that argument. Nevertheless, as leader of the group and her lover, he cared for her. But for the time being, he had more critical decisions to make. He should be grateful she smiled, mostly.

After lunch, Ryder took Dan and Jena out on the perimeter run. They were keen to breathe fresh air as well as inspect their security from the possibility of crazed local invaders. He had a strong urge to do the whole tour by walking, but Jena had spotted Brian's quad-bike and her playful side obliged her to insist on using it.

"Have you heard a quad-bike in action, Jena?" Brian, held onto the key, while Jena tried to grab it off him.

"Of course I have. Everyone has them on my beach in LA. No one would consider moving across the dunes without one."

"I thought you lived in Boston." Ryder had studied the biographies of all the crew.

"Oh, come on, Ryder. Stop being picky."

"It's not that I mind you having a great time."

"Great," Jena said. "Brian, hand 'em over."

"But we try not to generate noise that might bring unwelcome visitors."

"Antonio said the perimeter tour took four hours," she said.

"Hey," said Ryder, "if you've something better to do, don't let us keep you."

"Actually, I might have. You boys go for your hike."

Dan took Ryder to one side. "It might not be a good idea to leave Jena to her own devices. You might have noticed that she's a bit..."

"Volatile?"

"Excitable. Ryder, I know the quad-bike would be noisy, especially up on the ridge where the sound would travel all the way to Ireland, but I'd rather have her with us than not."

"Hang on a moment," said Ryder, and ran into the centre. Moments later, he came out with Megan's mountain bike. It had the latest puncture-proof tyres, thirty-six gears, and ultra-smart suspension system.

Jena snorted in derision but after a little consideration, tried it out around the centre car park. "Pretty cool. Give it a go, Dan. On the other hand, you can't-it's all mine."

"Actually, it's me who's allowing you to ride my bike," said Megan at the doorway.

"Oh, thanks, Megan. Does it do zero to twenty-five thousand in ten seconds like the vehicles I'm used to?"

"Only downhill. Brian's fixed the hooter."

"Great. Hey, the hooter doesn't work. Ah, that's what you meant. And I suppose he's taken the playing card out of the spokes as well, the spoilsport. Hah! Don't worry Megan, I'll bring it back in one piece."

"Before you go tearing up the valley," said Ryder, "there are a few ground rules such as keeping below the ridge, keeping quiet, get on the phone if you see a stranger within the perimeter, keep within sight of us at all times-"

"Haven't you got one of those retractable child leashes to put on me?" said Jena "I'll just have to trust you. Phone?"

"Yes."

"Helmet?"

"Get lost." She bombed off down the narrow lane.

RYDER AND DAN FOLLOWED ON FOOT. The valley had few trees. Bracken and grasses clothed the rocks, allowing a clear view for several miles. Ryder regretted letting Jena escape by mountain bike. There was no way she would keep them in sight, and they couldn't catch up. So, they turned uphill off the track to gain the ridge. Their view of the whole valley would be uninterrupted, and with care, they'd be able to use their binoculars on the next valley.

Dan had to keep stopping. "You've no idea what this hike is doing to my lungs and legs."

"I've some idea, Dan. I used to spend too long cooped up in offices and studios. It's only recently I've had the benefit of all this fresh air, the aroma of that lavender we've just brushed through, watching bees visiting the heather blossoms, and just gazing at the eddies in a mountain stream."

"No, Ryder, I mean I've been in low gravity and little exercise-mode for so long, I can't keep up."

"Oh, sorry, Dan. Head for that rock; we'll rest up."

They sat and trained their glasses on Jena. A mile away, she'd left the rough lane to explore the stone remains of ancient hut circles in the valley floor.

"Before we arrived here, feral ponies wandered throughout this valley. Just a small herd but no doubt they assumed it belonged to them. Luckily, we only had to patch a few holes in fences to persuade them to find other pastures." A splotchy brown butterfly alighted on a sun-warmed patch of rock near Dan.

Dan leant towards it. "Well now, little fellah, do you have ARIA? I guess it would be pretty difficult to compute its memory loss."

"Since the butterfly stage only lasts a week or so, it would lose its adult memory in four hours. What would it have to remember anyway? Instinct tells it to drink, fly erratically to avoid predators, warm wing muscles on a sunny stone, mate, and lay eggs. I think it must be one of the fritillary butterflies Teresa's excited about. They're becoming rarer, though whether it's global warming or habitat loss-hey, I suppose ARIA will result in them increasing. I'd like to show you the ridge. Shall we go?"

Dan took one more lingering look at the butterfly. At the ridge top, he gasped. Both out of breath and in awe of the view.