This part of Arizona, as well as pretty much the rest of Arizona, Jeffcott suspected, was pretty much nothing but desert. The land was wide, flat and empty except for a line of hills on the horizon. The road itself was the only man-made structure visible, except for a line of electricity pylons that followed it on one side. He knew that if he moved more than a couple of hundred metres from the road, he would see nothing to suggest that any other human beings lived on the planet. The scene was exactly as it would have been if he'd travelled a million years into the past.

He imagined that this emptiness probably seemed completely normal and natural to an American. For him, though, an Englishman, no part of whose country was untouched by the hand of man, it was as haunting and alien as being on the surface of the moon. It wouldn't have been so bad if there'd been some music playing. A radio, maybe, tuned to a country music station playing Kenny Rogers or Tanya Tucker. Here, though, inside the anomaly that soaked up radio signals like water trying to flow across blotting paper, there was nothing but the sound of the wagons creaking and groaning as they trundled along the road and the clopping of the horses' hooves on the hot tarmac. It should have filled the emptiness, become a comforting backdrop to the surrounding silence, but instead it only threw the silence into sharp relief. It somehow made the silence more complete, more suffocatingly total, than true silence would have been.

"This place makes me think of the prophets of the Bible," said Lucy Dennings. "And present day holy men who go out into the wilderness to commune with God. They claim it's easier to hear the still, soft voice of God without all the noise and clamour of civilisation."

She was speaking only to fill the silence, Jeffcott knew, but he was grateful for it. It was good to hear a human voice above the lonely whispering of the wind. "From the tone of your voice I gather you have another theory," he said.

"Well, maybe," the psychologist replied. "I'm not a believer in any religion but what do I know? Maybe there really is a God and maybe he really does need quiet emptiness to best communicate with us mortals. Now that I'm here, though, surrounded by silence and emptiness, I'm reminded of something called third person syndrome."

"What's that?" asked Rahul Bhatt. He also sounded grateful for the conversation.

"It's a phenomenon in which, in times of hardship or crisis, people imagine the presence of another person who doesn't exist or who wasn't there," said Dennings. "It happened to Ernest Shackleton during one of his antarctic expeditions. That would have been in 1917 or thereabouts. He was stranded in pack ice for over two years and had to walk overland to reach safety. During one march in which they walked for thirty six hours straight he said that he imagined that there were four of them walking across the ice, not three."

"That would be four man syndrome surely," said the Indian with a smile.

Dennings ignored the comment. "When he described his experiences it inspired others to come forward to recount similar experiences. Climbers, shipwreck survivors. Individuals, or small groups of people, isolated from other people in harsh environments. There's evidence that this phenomenon might be related to the concept of imaginary friends and guardian angels. The phenomenon has been replicated artificially in sensory deprivation chambers. You know, the ones where you sit in total darkness and silence until you begin to hallucinate." She looked out across the wide, empty Arizona desert. "Well, this place is like an outdoor sensory deprivation environment. Maybe those prophets and holy men only hallucinated their encounter with God as their brains, desperate for sensory input, started imagining an unreal companion as they tried to keep their owners from going insane."

"Who is the third who walks always beside you?" said Duffy thoughtfully.

"When I count, there are only you and I together

"But when I look ahead up the white road

"There is always another one walking beside you

"Gliding wrapt in a brown mantle, hooded

"I do not know whether a man or a woman

"But who is that on the other side of you?"

"TS Eliot," replied Jeffcott with a smile. "The Waste Lands. I read it as a teenager when a girl I was trying to impress recommended it to me. For some reason that passage stuck in my head."

"Mine too," said Duffy. "That guy knew how to write."

"Quite apt as well," said Dennings, "because Eliot claimed to have been inspired by Shackleton's experience. Eliot's third man in where the phenomenon got its name."

Duffy chuckled dryly. "If that's so," he said, "how long will it be before we start imagining unreal companions as well?"

"We're not going to be out here for forty days and forty nights," said Jeffcott, though. "We'll be in Maricopa in just a few hours. Hardly long enough for us to start hallucinating. If we geed the horses into a gallop we could be there in less than an hour. Even back in England that would hardly be considered a long trip, and you guys travel further than that for a couple of drinks in a bar."

"So good to know what the rest of the world thinks of us," said Dennings with a smile.

Jeffcott smiled back. "And unlike those prophets and holy men," he added, "we're not alone. Look at us, all bumping knees with each other and chatting. Keeping each other company." He glanced across at Robinson and Bright who were talking about old boyfriends. When they saw that they were the subject of his comment they glared at him before resuming their conversation in a lower voice.

"I wonder if those plants are being affected by the anomaly?" said Dennis Gruber. Not speaking to anyone in particular. Just throwing the thought out into the void to see if anyone picked it up. "I mean, I know that plants have a slower metabolism than animals, but they're living things and the anomaly seems to do strange things to living cells."

Jeffcott looked out at the stunted shrubs that dotted the brown, dusty landscape. "None of them look as though they grew vigorously even under the best conditions," he said, "and in the present dry and heat they're probably all but dormant. Waiting for the next decent rainfall, whenever that is. Perhaps if you looked at a thin slice of tissue under a microscope you might see some strange activity, but other than that..."

"Those plants have been inside the anomaly for less than a day," said Mark Summers, the other doctor. "And even the fastest growing plants only grow a few millimetres in one day. We're not going to see any plants showing any anomaly effects."

Gruber nodded, looking disappointed, and Jeffcott wondered how similar the embryonic development of plants was to that of human beings. Probably pretty similar in its essentials, he thought. After all, both animals and plants started out as a ball of cells differentiating for different tasks, forming different tissue types, and animals and plants were descended from the same common ancestor, if you looked back far enough. He'd spotted a microscope amongst summers' belongings when he'd come aboard. A simple thing of tubes, lenses and manual controls. No electronics to be affected by the anomaly.

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"I wonder if our escort would be willing to stop long enough for me to grab a few specimens?" said the doctor thoughtfully. "There might be insects, that sort of thing."

"Wouldn't they all be dead by now?" said Jettt.

"Not necessarily. Insects are incredibly resistant to radiation. The popular idea that cockroaches would be the only creatures to survive a nuclear war isn't that much of a myth. And if they can resist radiation, to a certain extent, maybe they're resistant to anomaly effects as well."

He looked up into the sky, probably trying to see if there were birds up there, but there was nothing but the silvery blue of the sky, unbroken even by clouds. Of course there wouldn't be birds, thought Jeffcott as he followed the Doctor's gaze upwards. They would all have been driven away by the sense of 'wrongness' that the anomaly generated as it approached. Animals would also have fled the area, except possibly for burrowing rodents unwilling to leave their homes. And, of course, he reminded himself, there were no aircraft in the sky. This close to a city of two million people there should have been a steady stream of aircraft going to and from it, but there was a no-fly zone over the whole area. The anomaly wasn't just circular, after all. It was a sphere, reaching down into the ground and up into the sky, currently reaching an altitude of eighty thousand feet above Maricopa. Some military aircraft might be able to go that high but he didn't think any commercial aircraft could.

Then he heard a shout. One of the mounted soldiers was pointing to something off to the right. They all looked and saw a man running across the arid landscape, waving to attract their attention. The convoy came to a halt and the Sergeant ordered two of his men to go and investigate. They galloped off, leaving the highway and rushing across the dusty ground, lowering their lances ready to skewer the man if necessary. The man stopped and raised his hands fearfully and the soldiers reined in their horses before him. A brief conversation took place, and then the soldiers walked their horses back to the road, the man walking between them.

The Sergeant and two more of his men rode out to meet him and the experts strained their ears to overhear the conversation. "Thank God!" the man sobbed gratefully. "My friends need help. They're sick. I can't wake them up."

The experts glanced at each other helplessly. A group of idiots who'd evaded the picket line, probably during the night, and entered the anomaly, driven by curiosity and the certainty that the authorities were hiding something. The man looked to be in his early twenties with bare, sunburned arms and a vest bearing the image of a cannabis leaf. He probably thought that the anomaly was caused by a crashed UFO or something.

"I'm sorry," the Sergeant told him. "We can't help you. If you follow the road, though, there's a hospital just a few miles away. They'll help you."

"I can't walk that far," the man replied desperately. "I'm sick. Radiation or something. I can hardly stay on my feet. You can take me on your wagon..."

"I'm sorry," the Sergeant repeated. "We can't help you. We're going that way. The hospital is that way."

"You can't just leave me here!" The man staggered towards the Sergeant, his hands outstretched, and the soldiers pulled their guns from their holsters, aiming them at him. The man recoiled fearfully, his eyes wide and staring.

"That way," said the Sergeant, pointing back the way they'd come. "The sooner you start, the sooner you'll be there."

"What about my friends?" The man begged. "They collapsed back there, just a little way back there. They're dying! You can't just leave them there."

The Sergeant was turning his horse to return to the road, though. His two men waited for a moment, still aiming their guns at him, then they holstered them and followed. The man stared in disbelief, then burst into a run, heading straight for the convoy. He was surprisingly fast and had reached the wagons before any of the soldiers could stop him.

"Please!" he begged, staring up at the experts. "Talk to them! Please! My name's Phil. I have a girlfriend back in Glendale and a baby on the way. She needs me! Please!"

Jeffcott stared at him in astonishment. This close, the man looked like a waxwork sculpture. His skin was an unnaturally even pink, as if he'd been coloured by a six year old child who had no idea how to capture the complex tones and hues of natural human skin, and it was shiny as if he'd been soaked in oil. He thought it was also a little transparent. He thought he could see a couple of millimetres below the surface, unless it was just an optical illusion caused by the oily surface.

The pupils of his eyes had shrunk so much that they were almost invisible leaving his pupils a solid disk of almond brown, a sight that caused Jeffcott to shiver with a revulsion that surprised him with its intensity. He radiated the same sense of wrongness that the anomaly itself had, before they'd entered it. That sense had faded now they were inside, but this man, standing so close that he could have reached up and touched them with his waxy pink fingers, brought it back to Jeffcott with full force. He gripped his spear and readied himself to bring it to bear against him while praying it wouldn't be necessary. He was suddenly certain that if he pierced his skin, his blood would be the same shade of pink. For some reason, the idea terrified him.

The two doctors twisted around to see him, their professional curiosity aroused, but then the Sergeant was giving the order for the convoy to proceed. The wagon jerked back into motion and the sick man clutched hold of the railing so that it pulled him along. "Please!" he begged. "Please!"

"Isn't there anything we can do?" asked Mark Summers. As a doctor, he had sworn an oath, but Jeffcott could see that the others were all feeling the same desperate urge to help the man; a feeling that warred with an instinctive desire to put distance between him and them.

"Even if we could get him to the hospital immediately, you've seen how little they can do," Rahul Bhatt replied. "Whatever they do for him would only prolong his suffering."

"What are you saying?" The sick man demanded. "What others?"

Then the Sergeant was there, reaching out from horseback to pull the sick man away from the wagon. "Away with you now," he said. "Either go to the hospital or go back to your friends. There's nothing for you here."

"Damn you!" the sick man swore at him. "Damn you to hell!"

He made a grab for the pistol the Sergeant was wearing on his hip. The Sergeant pushed him roughly away and the man fell with a gasp of pain as his hip came down on a rock. He climbed back to his feet with a snarl of rage and prepared to launch himself at the Sergeant. The Sergeant pulled his lance free from its harness and lowered its point towards him. The man ran forward and the Sergeant thrust its point through the man's heart.

There were gasps of shock from the civilians. The sick man's blood was red, it turned out. A spurt of it erupted from his chest as the Sergeant pulled his lance free. Then the man fell with a sigh as his last breath escaped him. Jeffcott thought the sigh sounded almost grateful, as if the man was finally free of some terrible torment. Maybe he was.

The Sergeant looked at the civilians as if expecting them to cry out in condemnation, but no-one did. "Probably the kindest thing that could have been done for him," said Dennis Gruber quietly. "Remember those poor souls back at the hospital."

. The Sergeant clearly thought so because he was wearing a determined, unrepentant expression that told them that he had no problem with the way things had turned out. He was replacing his lance in its harness, still looking at them. Then he turned his horse and returned to the head of the convoy, leaving the dead man lying in the dust.

"Let's go," he said. "We've got time to make up."

The three wagon drivers slapped their reins and they continued on. Jeffcott tried not to look at the dead man as they passed him, but his eyes seemed to be under the control of a power greater than his. The man had rolled onto his back, and the intensity of the situation made Jeffcott notice tiny details that he would probably have missed otherwise. The large bloodstain covering the cannabis leaf design on his vest was still growing as more blood leaked from his wound and dust was sticking to the oily skin of his arms and face. As their wagon passed him by, though, he thought he saw movement under his skin. Colonies of embryonic tissue, he assumed. Moving around inside the corpse, and now they had seventy kilos of dead meat to feed on.

He looked at the other experts. They were carefully looking away from the corpse except for Dennis Gruber, the expert on embryonic growth defects, who was staring at it with a horrified intensity. Was he imagining those embryos growing until they had nothing left to feed on? Jeffcott wondered. Was he imagining small but utterly monstrous creatures tearing their way through the skin and wriggling off in search of something else to eat? Jeffcott thought he was, because he was imagining the exact same thing.

Gruber tore his gaze away from the corpse with a visible effort and for a brief moment his eyes met Jeffcott's. They each read what the other was thinking and they tore their gazes apart as if jerked by an electric shock. Jeffcott noticed that the doctor avoided looking at him for a long time after that.