"All status green," called one of the researchers, watching a series of readouts on his screen. The batteries and capacitors were fully charged. All temperature and current sensors were within the expected range. The CCTV feed showed the room empty of speeding toddlers being chased by their parents. And boy, had that been a shock. With all the radiation flying around in there, back before they'd achieved anywhere near useful levels of containment or stability, it was a miracle none of them had suffered any noticeable consequences.

Their sponsor had even ordered them not to apprehend the intruders or file police reports of trespass, in case it came out that they'd dosed them with goodness knows what. Attracting attention was the exact opposite of what they'd wanted to do back then, so ever since, they'd simply made very certain the fire escape was kept locked.

"Activation in three... two... one..." called another worker.

The building was filled with a low-pitched hum and the live feed of the equipment lit up with the usual blue glow. As stability grew, the hum grew quieter and the glow dimmer, but they were a long way off perfection. Perfection wasn't the aim, anyway. It just needed to be good enough to extract more power than the equipment consumed.

"Early indications indicate a two percent reduction in power draw from the remodulation."

"Only two? We were hoping for four or five."

"I think we overshot. We're getting increased attenuation at the higher frequencies."

"We'll have to take a closer look at the readouts once the test completes."

"Hmm? Did anyone else just hear a ding?"

"Not me."

"I did. Some sort of high-pitched chime."

"Probably a bit of equipment settling. Nothing to worry about."

The team continued watching their displays. In truth, the tests themselves required very little work; the computers did everything automatically. It was the following week—analysing petabytes of collected data and tweaking the parameters for the next test—that required the most effort. While a test was running, they simply looked at screens and made trivial observations. Usually.

"Something's wrong! Power output just started dropping."

"Confirmed! We're down forty percent. Fifty. Sixty. And it's still falling!"

The hum that filled the room changed, losing some undertones and harmonics and morphing into a flatter growl. The blue glow flickered and dimmed.

"Zero! Power output has dropped to zero!"

The workers stared at their displays, unable to comprehend what was happening.

"All systems are still green. No obvious problems. This shouldn't be happening."

"Is it possible that we've completely drained the supply of energy?"

"It... shouldn't be. Our theories suggest that the energy we should be able to extract from the vacuum is infinite."

"Well, something just happened. Does anyone... Wait, did you see that?"

"See what?"

"On the live feed of the experiment chamber. Something flashed at the edge of the containment sphere. Twice."

Every worker in the room peered at the display, and thus every worker in the room was watching as a triangular section of the sphere fell away. Alarms blared as a burst of gamma radiation triggered the sensors in the experiment chamber, no longer safely contained within the sphere of titanium-lined lead.

"Kill it! Shut it down!" shouted the lead researcher, Dr Harry Withermark, causing one of his juniors to reach for a sizeable red button. Alas, he paused when something crawled out of the new hole in the sphere, leaping through the air and landing on the concrete floor below.

"... What?" Muttered someone.

"Is that... a hand?"

"It's moving. And it's holding something?"

Someone rotated the camera and zoomed in on the thing. It was indeed a hand, the wrist hidden in a shimmering black cloak, and it was indeed holding something.

"That's an eye!"

The eye was almost completely shrouded in the same black haze as the wrist, only the pupil, iris and small amount of sclera visible.

"It's looking at us!"

"I said shut it down!" screamed Dr Withermark, and finally someone did. The hum vanished, leaving the room in silence as everyone continued to stare at the screen. The hand-eye thing collapsed like a puppet whose strings had been cut and the haze evaporated away. A small pool of blood formed around the wrist.

"What just happened?" someone uselessly asked. It wasn't as if anyone else had any more idea than he did.

"Is that an alien? Should we call the government?"

"Oh? Do you have a phone number for 'the government'?" snarked someone else.

"No—we call no-one. At least, not yet. This... is just a prank. Probably. Do we have biohazard equipment?" asked Dr Withermark.

"The radiation suits should keep out most stuff, at least for a while."

"Right... I'm going to... umm... look at things in there. Does anyone want to volunteer to help?"

There were, surprisingly, several volunteers, and so it wasn't long before Dr Withermark and one of his juniors were inside the experimental chamber, in hazmat suits, poking at a dead hand.

"It's... a hand," commented the junior. "And that's an eye."

"Yes, it's definitely a hand. And an eye."

"A human hand. And an eye."

"Yes, it definitely looks human."

"But it was moving. It was pointing the eye at things. It..."

"I know! I was there!"

"I think we should call the police in. If this is a prank, using a human hand was..."

The junior stopped, interrupted by the sounds of smashing glass. The pair of them spun around, but there was no glass in the room, and the sound seemed to be coming from everywhere.

"What is..." started Dr Withermark, before his subordinate interrupted.

"Up there!"

In front of the containment sphere, which wasn't a functionally important part of proceedings but was there to keep the flood of ionising radiation away from the parts that were, the air was shimmering violently, as if a heat haze had been dialled up to eleven.

"What the..."

Keeping enough presence of mind to react, Dr Withermark ran to the far wall, lifting the perspex cover of the emergency power shut-off and hammering it, plunging the room into darkness.

The noise continued, unaffected by the loss of power to the entire facility.

"This... isn't us..." mumbled the junior, staring at where the distortion had been visible before the room was plunged into darkness.

Dim violet lightning flashed silently in the air, before the emergency lighting kicked in, once again revealing the distortion, now two metres across and still growing.

"I... think 'the government' is starting to sound like a really good idea."

"You think they would have any more clue about this than we do? You think anyone would? There's a reason our sponsor still pays for this place."

"In that case, how about running for our... lives?"

The voice of the junior researcher trailed off as the distortion changed. It folded in on itself, appearing smaller apparently without changing size, as if it were growing more distant. But before it vanished completely, the shimmering haze cleared up. For a single, long second, there had been a fully transparent hole hovering in the air, before it snapped shut with a pop.

"Did you... see that?"

"You mean... people?"

"I did note one of them was missing a hand and an eye."

"I noted what he was standing on."

"I was trying to forget that bit."

The pair of researchers stared in silence for a full minute before Dr Withermark once again spoke.

"We haven't been drawing energy from some fundamental property of space. We've been drawing it from another universe."

"One with dragons."

"And now they not only know we exist, but we've taught them how to open portals here."

"So, who was it who had the phone number for 'the government'?"

Twenty-four hours later, the small band of scientists were discovering that 'the government'—previously thought of as a lumbering beast that took a full year to get dressed each morning, serving only for taxes to enter one orifice and bureaucracy to be excreted from another—could actually move quite quickly when an alien hand and eyeball popped into existence and bled out over the floor of their research facility.

Dr Withermark was seated at a cheap, coffee-stained table, the research group never having gone in for expensive furniture, not expecting the presence of prestigious guests at this stage of development. Today, they had some very illustrious guests indeed, not least Gregory Charles, the government's minister of foreign affairs, who had recently and somewhat reluctantly had his job scope expanded to include affairs that were rather more foreign than he was used to.

"The lab has sampled the DNA of the hand, eye, and bacteria found living on them," reported one of the overly dressed newcomers. "Firstly, they confirm that all do contain DNA, and that it consists of the usual four base pairs. The hand and eye are also confirmed to come from the same individual. Beyond that, things leave the realm of the expected. A proper analysis will take weeks, but so far we can say that while the DNA of the supplied body-parts bears much similarity to humanity, sharing our chromosome layout and most genes we've checked for, there are never before seen alleles present. While it's still too early to draw firm conclusions, our current best guess is that the DNA is from a human population that last interbred with our own at some point between a thousand and a hundred thousand years ago."

Gregory Charles—the most immaculately dressed of the visitors, his shoes shiny enough to shave in and the contrast ratio between his black jacket and white shirt putting even the most advanced video displays to shame—frowned at the imprecise guess, but refrained from interrupting. Given the time constraints, he knew they were far from performing a proper analysis.

"As for the bacteria, we've got nothing. They don't match any known families on Earth. We aren't even sure they are bacteria; it would be more accurate to call them unidentified single-celled lifeforms. The most we can say is that empirical evidence—the fact they were growing on an effectively human hand—suggests they thrive in Earth-like conditions. A full analysis could easily take years, but for now, we must recommend the very highest biohazard containment protocols."

"Agreed," nodded Gregory, which left Dr Withermark wondering just how much higher those containment protocols could get. There were already dozens of outsiders crawling over the entire facility, blasting everything with levels of UV high enough to cook a person in seconds. The clothing he'd been wearing on his trip into the laboratory had long since been burnt, despite the protective gear over the top, which had also been burnt. "And the report on the damage to the containment chamber?"

Another of the newcomers spoke up, glancing down at a sheet of printed paper containing more than the usual number of exclamation marks for a scientific report.

"It was cut through, physically. No sign of heat, chemical damage or abrasion; it was a trio of simple, physical slices. They do note that two of the cuts are cleaner than the other. Matching up to the video footage, it was the second cut that was the odd one out. They confirm there is no known material that could slice through the titanium shell in the way seen, even ignoring the lead interior, and can offer no explanation for how it was accomplished. The report concludes with the sentence 'the incident described is not physically possible'."

"So we have alien biology and exotic materials. We have all seen the videos. Does anyone else have anything to add?"

"If I may," spoke up Dr Withermark, managing to hold his voice steady and keep his trembling barely perceptible, "there was one further incident that occurred after I hit the emergency kill switch and the video recording cut out. I haven't mentioned it before because it sounds so stupid, and without the other evidence, I couldn't see anyone believing it. As the portal collapsed, for a couple of seconds, it became transparent."

He hesitated under the pressure of the stares of the half-dozen officials. "You've already said this. You saw a city," stated the minster.

"Yes, a city. The portal in the air above it. Blue skies, fairly normal looking buildings, etc. What I didn't mention were the individuals standing in front of the portal. Three of them. A girl and a boy, in their late teens. Maybe seventeen. The boy was missing his left hand and eye, and his skin and eye colour matched the... specimen. There was also a much younger boy, of six or seven. The older pair had feline looking ears, and the girl had a tail. And the three of them were standing on... a dragon."

"A... dragon..."

"A dragon. Red scaled, horned, hovering in the air on massive wings, staring straight into the portal."

"You're right. I wouldn't have believed it. I'm still not sure I do. So, in summary. You people here have, without even realising it, been opening portals to another world in an attempt to develop a new power source. People in this alien world can, apparently, breach the laws of physics on a whim, while riding dragons. And now they've not only learnt about our existence, but also know how to get here. Is there anything I've missed?"

The other occupants of the table remained silent.

"Can we prevent them opening portals here? Either globally, or in specific areas?"

"Not in any way we know of," answered Dr Withermark, now (reluctantly) the world's foremost expert on interdimensional portals.

"Do we have any way of defending against what they used to cut through the containment sphere?"

"We don't even know how they did it. I can't even begin to guess what it would take to defend against it."

"So, if they decide to attack, they could appear in any place, at any time, with weapons that can slice through anything."

"Perhaps things aren't quite as bad as that. They did open the first portal here, after all. Maybe... our experiments weakened space, somehow, and they can only come out here?"

"Do you have any actual basis for believing that, or is it just wishful thinking?"

"... No."

"Then, for all we know, an army is already pouring out elsewhere. There will be an emergency cabinet meeting held in two hours, in which I'm going to have to confirm the discovery of alien life, and then we're going to have to decide what to do about it. The way I see it, we have two choices. First, burn this place, bury this incident, and pray to whatever gods we believe in that nothing comes for us in the night. Second, reopen the portal and attempt to establish diplomatic relations."

Dr Withermark thought back to the brief glimpse he'd had of the quartet of faces through the portal. He wouldn't like to claim any expertise in the reading of draconic facial expressions, but the two older humanoids had looked... frightened? Shocked? Certainly not like they were about to launch an invasion. The younger one had a much clearer expression; it was one he saw on his co-workers every day. Pure, unbridled curiosity.

"I realise that a glance at a few faces isn't the best indicator you could have, but from what I saw, I think speaking to them would work."

Then he considered what appeared to be a remote-control hand, a knife that could cut titanium like butter, and the dragon.

"Besides, both options are risky, but imagine the potential rewards if we can establish a trading relationship."

Gregory nodded in agreement. "How soon could you establish a new portal?"

"If we stop caring about energy efficiency and radiation emissions, we could do it in a couple of days. Or around a week if you want people in the room without being fried by gamma rays; we'll need to think carefully about how to build shielding while leaving the portal accessible."

"I'll be in contact again within five hours for confirmation," replied Gregory, standing up, "but I suggest you start that careful thinking immediately."