"What's that noise?" asked Private Seabreeze.

He and Parrott had been searching around, looking for a grassy field where the horses could feed. The only vegetation, though, was the weeds growing in the gardens of the newly built and mostly still empty houses across the street. They'd taken the horses across to them, but the horses had only given them disappointed looks before waiting patiently for their human masters to bring them some real food. Their real food had been on the supply wagon they'd lost on the way, though. The horses had to either content themselves with the weeds or starve.

The noise was coming from the laboratory building behind them. A kind of chalk-on-a-blackboard noise that grated on the nerves. "What the hell is it?" asked Seabreeze, tensing up anxiously. It was impossible to avoid the idea that it was an alarm call, as if something inside was calling for help.

"It's coming from the top floor," said Parrott, looking at the open windows. "The others were looking for the basement."

"So what do we do?"

"Our orders were to look after the horses and keep watch," Parrott replied. "We obey our orders until we receive different ones."

Seabreeze nodded, feeling relieved. The other soldiers, older than him by several years, was taking charge. Taking responsibility, which meant that nothing that happened would be Seabreeze's fault. He could just relax and obey orders, which was the way he liked it.

Parrott was frowning though. Feeling the responsibility he'd taken upon himself. "What's going on in there?" he muttered. "What the hell's making that sound?"

"It's horrible, whatever it is," Seabreeze replied.

"We should get back over there," said Parrott. "We've wandered too far away. We're supposed to be guarding the doors."

"What about the horses?" asked Seabreeze as he followed the other man back across the street.

"They'll be okay. They'll eat when they get hungry enough..."

He was brought up short by the sound of breaking glass behind him. One of the windows of the newly built house had shattered, glass showering out to fall in sparkling fragments to the bare earth below it. The two men jumped back, raising their spears to ward off any enemy that might suddenly appear, but there was no human enemy to be seen.

"Having another of them damned hallucinations," said Parrott unhappily. "The eggheads said to just ignore them, but this one's bloody horrible."

Seabreeze laughed. "So long as it's not a flower with eyes on it," he said. "Looking down at..."

His voice broke off at the look of shock that suddenly appeared on the other man's face and then they both looked back up at the thing emerging from the window. It was making its way down the wall with alarming speed, clinging to the brickwork like a fly. Behind it, another appeared in the open window, and more windows were breaking in other houses as the creatures emerged from them. Soon there were dozens of them jumping the last few feet to the ground. Their globular elements broke apart from each other as they hit the ground, but then they pulled themselves together again. Seabreeze saw the globular elements of three of the creatures merging to form a single large creature with three flower-heads. It's eyes fixed on the two humans, and then it began to emit the same chalk-on-a-blackboars sound as it advanced towards them, the others close behind.

The two soldiers reached the doors of Kensington Labs and raced across the reception area to the corridor that led away from it. Parrott slammed the wooden door shut and then they stood back from it, facing it with their spears in their hands.

"The whole front of the building's made of glass," said Seabreeze, glancing behind it at the other doors lining the corridor. "Fragile glass."

"Parrott!" cried a voice behind them. One of the doctors. Seabreeze couldn't remember his name. "Monsters!" He pointed upwards, at the floor above them.

"More monsters," said Parrott, pointing at the door behind him. "Lots of them. Where're the others?"

"They went down to the basement."

"Go tell them what's happening. Tell him there're dozens of them."

"Yeah." Dennis Gruber ran down the corridor in the direction the other soldiers had gone.

"We can't stay here," said Parrott, looking around nervously. "They can enter the building at any point. We need to find somewhere..."

"Parrott?" came a voice from up the stairs. "Is that you?"

"That you, Tonto?"

"They're in the building already. Fall back to the east. That's where the stairs are going down to the basement. We can hold a line there, protect the civilians, and have a secure rear."

The tale has been stolen; if detected on Amazon, report the violation.

"But we'll be surrounded with no exit."

"We're already surrounded with no exit. Fall back."

Parrott and Seabreeze glanced at each other, then began backing away from the door. Around them came the sound of breaking glass.

☆☆☆

Duffy and Jeffcott led the way down the stairs, the other experts close behind them. They were each carrying a plastic light stick but soon realised they didn't need them.

"There's light down there," said Jeffcott. "Could that be the Furnace?"

"I don't see how," the other physicist replied. "Nothing electric works in here."

"Magnetic fields protect us," pointed out Jeffcott, "and the Furnace uses magnetic fields a thousand times more powerful. Maybe a field that powerful can allow electrical devices to work."

"Let's go see."

They increased their pace and reached the bottom of the stairs to find a short corridor with doors along both sides and at the ends. The light was coming from the door at the eastern end, which was standing ajar. There was a humming coming from it and a vibration of the kind that would be made by a powerful electrical generator. The air carried the faint smell of ozone.

"Last time I was here, that was a lecture room," said Jeffcott. "Big with a high ceiling."

"Let's see what it is now," said Duffy. They crept warily to the door, pushed it the rest of the way open and looked in.

The Furnace was a ring of tubular segments almost hidden beneath a layer of electrical cabling. It was half way between floor and ceiling, supported by a dozen concrete pillars. A generator stood beside it, connected to it by a fat power cable, but what seized their attention and made them stare in astonishment was what they saw inside the ring.

It was another place. Looking at it was like looking through a window at a strange foreign land except that the edges were fuzzy and distorted. When Jeffcott moved to the left his view shifted, showing the view from a slightly different angle, and he had no doubt that if he crossed the room he'd be looking in the exactly opposite direction, back at where the others were standing except that the 'window' would be in the way.

"Is that..." began Rahul Bhatt hesitantly, as if expecting to be mocked by the others for the very suggestion. "Is that a wormhole?"

"No," Duffy replied, almost breathless with excitement. "Spacetime is clearly flat here. It's two regions of spacetime pressed up against each other. A part of our universe and a part of another. I told you that certain results we were getting from CERN can best be explained if our universe was rubbing up against another. In that area, they've actually merged together. Anything in that area can't decide which universe it's supposed to be in."

"You wrote a paper suggesting that might be possible," said Jeffcott. "We all said it was nonsense."

"The two universes couldn't merge together before," added Duffy with a triumphant look at Jeffcott, "because their Bergmann Lorenz Torelli factors were too different. Like trying to mix oil and water, but if the Furnace changed the BLT factor in this part of our universe, even if just by a little bit..."

"The two universes would merge together," Robinson replied. "Just here, in this one spot."

"Wait a minute," said Jeffcott, though. "Let's not get carried away. We haven't ruled out that it's an anomaly hallucination yet."

"Describe what you see," said Duffy, still grinning with excitement.

"A landscape," Jeffcott replied. "Blue sky above sandy ground strewn with gemstones. Strangely regular hills in the distance, like a row of pyramids. Patches of some kind of vegetation. No, they're crystal growths of some kind."

"The pyramids sold it for me," said Duffy, though. "You're seeing what I'm seeing. It's real. We're looking at the surface of another world."

"In another universe," Robinson replied, staring in wonder and fear. She took a half step closer to Jeffcott and held his hand. It was slippery with nervous sweat. When their shoulders touched, Jeffcott felt that she was shivering.

"And the natural laws must be broadly similar to those in our own universe," she continued. "The place is lit by sunlight, so there are fusion reactions going on in a star somewhere. That means that physical processes perform much the same as they do here."

"Could we step through..." began Duffy.

Jeffcott grabbed his arm and held him tight. "Don't even think about it," he said. "There may not be any oxygen in the air over there. It could be toxic."

"The air in that universe will be mingling with ours," said the other physicist.

"No, it can't be," Jeffcott replied. "The chances that the atmospheric pressure over there is the same as here is tiny. If air could cross through, there'd be a hurricane blowing, either from our world to that one or in the other direction. There must be some kind of barrier, and a good thing too. Think of the microbes there might be in that atmosphere. Spores, airborne seeds... Or our microbes would be contaminating that world, if the wind were blowing in the other direction." Duffy nodded his reluctant agreement.

They heard feet on the stairs and turned to see the Sergeant running down to them. "Is there another way out of here?" he asked.

"There should be a service entrance," said Robinson, looking around the perimeter of the large room. "Why?"

"Can hostiles get in that way?"

"It's probably steel, so who knows? I don't know how strong it'll be by now."

The Sergeant glanced around the room, looking for it. "Keep an eye on it," he said. "You work on that thing." He pointed at the Furnace. "We'll try to make sure you're not disturbed."

"Disturbed by what?" asked Bright.

"Monsters," said Gruber, appearing behind the Sergeant and squeezing past him. "Emerging from the corpses of the dead. They're surrounding the building. Dear God!" He stared at the other world visible in the centre of the Furnace. "What the hell is that?"

"I call it Wasp," said a voice from the other side of the room.

The experts stared in surprise as a man emerged from behind the generator. He was wearing a crumpled lab coat that he'd clearly been wearing for some days. He looked to be in his fifties and had several days of stubble on his face.

"After the planet WASP-37 b," the man continued. "A hot Jupiter Thirteen hundred light years from Earth. The James Webb Space Telescope detected evidence of quartz crysyals in its high-altitude clouds. Since that world in the other universe us clearly a crystal planet, the name seemed obvious."

Bright noticed that Jeffcott was staring at the newcomer with astonished recognition. "You know this man?" she asked.

"I certainly do," Jeffcott replied. "Unless I'm suffering another anomaly hallucination, this is Professor Ernst Jorgensen Bergman. The chief researcher here and the creator of the Furnace."

The other experts stared in amazement as Bergman bowed his head to them in acknowledgement.