The first time she saw them, it was in Rovaniemi, Finland.

This was fair enough, since it was famously the home of Father Christmas and indeed she had been in the legendary “Santa Claus Village” tourist trap at the time. It had been a combination field trip, family holiday and reward for acing her first-year zoology course at university, and she’d jumped at the opportunity to witness the midnight sun, do a little research for her intended thesis, and get out to the palsas and check out some serious permafrost.

The end of June wasn’t the most Christmassy time to go, but it was also about the furthest you could get from the 0°Kelvin that was said to grip the country in winter, so that was a good trade-off. She and her family had also been ignorant of the fact that an overwhelming majority of northern Europe completely shut down over the summer. Indeed, it would be inaccurate to say she had been in Santa Claus Village, so much as near it. Santa Claus Village, along with most of the rest of Lapland, was closed for business while the native population performed slow iguana-blinks and basically tried to absorb as much sun as they could before the mosquitoes drained them to husks.

Ana-Lennox Medianu[1] – her friends called her Lenny – was twenty-three years old, studious but not lacking in a sense of open-minded wonder in the world around her. She was also possessed of a dark sense of humour that immediately made a stout friend of their Sami tour guide, a friend-of-a-friend of her dad’s who had been delighted to meet up with the exotic foreigners. She called him Renée, not just because she felt like a douchebag every time she mangled the pronunciation of his real name but because on the car ride from the airport he had told them “that Renée Zellweger is Sami, do you this know?” no fewer than four times.

[1] Her parents were big fans of Eurythmics, but that’s not important right now.

Anyway, she did have her daydreaming side, but when it came to reindeer she was all business, all herding and movement and mating habits and population distribution and hereditary disorders and ecological impact. The idea of Father Christmas’s reindeer, magical flying creatures that pulled Father Christmas’s sleigh while he delivered presents to the children of the world, was a cute and fanciful one but she’d never once considered it to be remotely factual, not even in terms of a fact-based origin for folklore or myth. Her only interest in Father Christmas’s reindeer was that there were quite a few around Santa Claus Village and she wanted to look into the differences between the handsome tourist-supported strains and the wider herd populations.

Imagine her surprise.

It only happened a couple of times. The thing about rangifer solis invicti was, they didn’t just look like normal reindeer. They almost literally were normal reindeer, in every meaning of the concept as defined by known science. They existed only in a specialised region, a sort of different layer of perception that Ana[2] would come to know as slo-time. There, they were rangifer solis invicti. But their slo-time reality also cast a sort of a shadow – a placeholder – into the real world, and those placeholders took the form of rangifer tarandus. Because that was just the least-resistance alternative. She never really quite figured out whether they could co-opt the extant reindeer-shaped space-time of any terrestrial reindeer, or whether they extruded themselves into this layer of perception and thus rearranged observed reality so that there had been a reindeer there. There were too many unanswered questions, and puzzles that current scientific theory was just not equipped to tackle.

[2] Her friends called her Lenny. You laughed at that Eurythmics reference.

Whatever the mechanism, they blended in perfectly with the other reindeer, while out there they flitted around doing who-knew-what, merrily disregarding time and space and relativity and – yes, sometimes – helping deliver presents to the children of the world. And, that weird summer in Rovaniemi, they pressed up against the paper-thin walls of the universe close enough to Ana that she could see them, touch them … talk to them.

She briefly considered writing a paper on it but – being the sensible person she was – decided to get verification first. It became immediately apparent that nobody else could see the reindeer or even knew about the strange side-on world in which they lived, and if she attempted to release any sort of serious academic work on the topic she could kiss her degree and credibility goodbye forever. “The sentient pan-dimensional flying reindeer is a biological reality,” said no seriously-considered zoologist ever.

So Ana did what any sane person would do. She put it down to a mild hallucinatory effect caused by two weeks of near-perpetual daylight, her poor adjustment to sleeping with an eye-mask on, and the excitement and romanticism of visiting the Home of Father Christmas. She went home, gathered her findings on the real reindeer and their environment, and went on with her life.

Then she started having the dreams.

They were dark and jumbled at first, confusing and wreathed in a misty blue-greyness that she’d never experienced in a dream before. They awakened her in the middle of the night with an indefinable anxiety, a sense of wrongness and disorientation, motion-sickness and a weird illusory effect that turned every shadow in her room momentarily into gnarled arcs of antler.

September turned into October, the winter storms of her homeland passed gradually in favour of the rising clammy oven-blast of summer, and the dreams began to clarify. It was as though someone was twiddling a reception dial in her head, trying to tune it to an extremely narrow, extremely obscure station.

The last dream she had, before the reindeer began appearing in her modest university-housing flat, came on the first of November and it was linear, visually flawless, clearly-narrated and as coherent as a television show being projected onto the insides of her eyelids. She awoke with the entire story crystal-clear in her mind, and it didn’t fade as the day continued, the way dreams normally did – certainly not once she had scribbled the whole thing down, filling half an exercise book with close-scrawled handwriting like some sort of sociopathic serial killer. It went on and on, layer upon layer and absurdity upon absurdity, but it boiled down to a single central warning.

Runaway Elves from Santa’s Workshop were going to cause the end of the world, and they were going to use Santa to do it.