The experiment was still running. Red laser beams sliced the air between an array of mirrors; lenses caught and shattered light; magnets pulsed their strange attraction. The equipment had been set up with precision and skill, and not a single detail was out of place. 

Except, of course, for the lifeless body of the experimenter herself, lying on the floor beside her experiment. 

The small group of men who had gathered to inspect the scene were not strangers to violent death. They had made their peace with it during their years of service to the company; sometimes they had even been the ones to order it. But they had certainly not ordered this. Dr Palomo’s death posed a grave threat to the secrets contained in this underground laboratory, secrets these men had devoted their lives to protecting, and for a long time no one seemed able to break the horrified silence that hung over the room. 

Dr Mulholland was the first to speak. ‘You know what this is, don’t you?’ he said, gesturing at the scene. 

The others looked at one another, baffled. ‘Please,’ said Mr Segher at length. ‘Enlighten us.’  

‘But you must see it!’

‘What exactly are we supposed to be seeing?’ Segher asked.

Mulholland gestured again. ‘Schrödinger’s cat! This whole setup - it’s quite clearly meant to be Schrödinger’s cat!’

He paused expectantly, but his colleagues continued to look puzzled. ‘I don’t understand,’ said Mr Westermann, glancing around as he was if expecting to see a real cat emerging from a shadowy corner. 

‘The room was full of hydrogen cyanide when they found her,’ Mulholland said impatiently. ‘And the gas canister was programmed to respond to the measuring device. It all fits! I’m telling you, the whole thing is a kind of macabre tribute to Schrödinger’s experiment.’

‘You’re imagining things. You must be,’ said Westermann. 

Mulholland gave him a withering look. ‘With all due respect, Hasse, I don’t think I am.’ 

Westermann cast a look of appeal at Segher. The director was still gazing pensively at the body, but after a moment he heaved a sigh and turned to his colleagues. ‘Well, I know Schrödinger’s cat is supposed to be both dead and alive at the same time. But as far as I can tell, Dr Palomo seems to be quite definitely dead.’ 

The other men glanced at one another, unsure if it would be appropriate to laugh. Mulholland cleared his throat repressively. ‘We must be dealing with someone very unbalanced. Obsessed, even.’

‘And it could only have been one of the researchers or technicians,’ Westermann was quick to point out. ’No one else has access to this lab.’  

‘Yes – which is why we need to decide quickly on a course of action,’ said Segher. ‘I mean, we can hardly go to the police.’ 

There was no disagreement from the other members of the board. Under no circumstances could the police be given access to the contents of this laboratory, or to the true nature of Dr Palomo’s research.  

‘Why can’t we just have Lynes investigate?’ said Westermann. 

‘Lynes is a security professional, not a detective.’ 

‘He’s good at what he does. We haven’t had a single major security breach since he was appointed — ’ 

‘Up until today,’ said Segher, looking pointedly at Dr Palomo’s body. 

It was hard to argue with this while the corpse still lay on the ground in front of them. Segher paused to let his words sink in, then said briskly, ‘I think we should look at getting someone in from the outside. A man with some expertise whose discretion can be bought – ex-police, maybe, or a PI.’

‘Hmmm,’ said Westermann doubtfully. ‘We’d have to be very careful about what we told him.’

‘Of course,’ said Segher. ‘He doesn’t need to know exactly what she was working on.’ 

Mulholland frowned. ‘You don’t think the reason she was killed might have something to do with her work?’ 

Segher took his time replying. ‘I very much hope not,’ he said slowly. ‘Because if it does, then we have a very serious situation on our hands.’ 

Chapter One

When Cleo woke, she had no idea where she was. 

For several minutes she simply lay there gazing hazily at the floor, the only thing she could see from her current vantage point. She had never lived anywhere with carpet like this, so thick and rich it looked as if a person could drown in it. And were these sheets really satin? She would never have bought satin sheets for herself: even the sound of the words felt unnecessarily self-indulgent.

She closed her eyes against the glare, allowing her head to clear. The air smelt of sandalwood and vanilla, creamy and clean. But she was beginning to remember. Denmark. Copenhagen. The expensive hotel by the Tivoli gardens.

And that strange encounter last night. 

She had been in the bar by the lake until close on midnight, drinking on her own: these days she flinched from human contact, and yet whenever she was alone she found herself pacing in circles, her heart speeding up, her hands flittering like caged butterflies across the walls and doors. When she’d eventually left the bar and started walking back towards her hotel, all of a sudden she’d felt the night crash over her, vast and desolate, and she'd thrust her hands into her pockets, tilting her head to look at the sky. Her breath had come fast like she was laughing, or perhaps crying, she had no idea which. 

Then a voice from behind had said, ‘Hey there - are you ok?’ 

Cleo’s head snapped back down. ‘I’m fine,’ she said coldly. 

‘Are you sure? Because you looked - ’ The man stopped, rubbing his face in some confusion. 

‘I’m fine,’ Cleo said, still more coldly. ‘I was just leaving.’ 

The man glanced up the path. ‘You’re going to the Tivoli Royale? How about I walk with you?’ 

‘I can find my own way,’ Cleo said. 

‘No, no, I insist! I’m actually on my way there myself.’ 

Without answering, Cleo swung around and began walking again, but to her annoyance, the man hurried after her. ‘I’m Owen Sutherland, by the way,’ he panted, bobbing at her shoulder. 

Cleo did not look at him. ’Cleo Brookson,’ she said unwillingly, still not accustomed to the way the false name felt on her tongue. 

‘You’re here for the holidays? What a beautiful place to spend the festive season. Sadly I’m only in the city on business, but I’m hoping to hit up the Christmas market in my free time.’

‘Right,’ Cleo said, wishing he would just stop talking. They were walking deeper into the wooded part of the Tivoli park now, and without his chatter, the shadowy stillness might have felt peaceful. 

‘Have you been to Copenhagen before?’ Owen asked. 

‘No,’ Cleo said shortly. 

‘I’ve been here many times. Maybe I could show you round the place if you’re free some evening?’ 

‘No thanks.’ 

‘Really, it would be no trouble.’ 

Cleo halted abruptly. ‘Oh, for - could you please just leave me alone!’ 

Owen looked injured. ‘I was just being friendly.’ 

‘Sure. Friendly,’ Cleo said bitterly. 

And then suddenly another voice floated towards them out of the shadows ahead. ‘Come now Sutherland. Seems like the lady’s made her position clear.’ 

Cleo’s heart scissored in her chest, and immediately she hated herself for the moment of panic. She made to keep walking, but the stranger stepped out into the path to block her way. The motion seemed somehow effortless, as indeed everything about him seemed effortless: he appeared to inhabit rather than merely wear his expensive suit, and his advance on Cleo and Owen felt as inevitable as gravity.

‘Sutherland,’ he said, his eyes fixed on Owen. ‘Long time no see.’

 ‘Kerr - ’ All of a sudden Owen’s voice had lost all its smooth self-assurance. ‘I - I didn’t know you were in Copenhagen.’ 

‘I thought I’d pass on my season’s greetings in person.’ Still without looking at Cleo, Kerr added, ‘Run along, kid. Sutherland and I have business to attend to.’ 

Cleo glanced at Owen, who was looking distinctly panicked. ‘What’s going on? Who is this man?’

Owen ignored her. ‘Kerr, there’s no need for this. I was being straight with you - I’ve done what I can, but Elsinore aren’t playing ball.’ 

‘If you’re holding out on me, Sutherland - ’ Kerr growled. 

‘It’s the truth! No one’s said a thing about a quantum computer.’ 

Kerr opened his mouth, and then appeared to notice that Cleo was still there. ‘Like I said, kid, get out of here,’ he said impatiently.

‘No,’ Cleo said. 

Owen glanced nervously between her and Kerr. ‘Cleo - look, it would really be better - ’ 

‘I’m calling the police,’ Cleo said.

Kerr looked amused. ‘Come on now, there’s no need for that. I’m not bothering you, am I?’ 

‘You’re clearly bothering Owen,’ Cleo said. 

Kerr stared at her for a moment, and then began to laugh. ‘Oh this is beautiful!’ he said, turning to Owen. ‘You need little girls to look after you now, Sutherland?’

‘This has nothing to do with me!’ Owen protested. 

‘Then deal with it,’ Kerr said briskly. 

Owen turned to Cleo. ‘Look, I - I appreciate your concern, but you don’t need to - Mr Kerr is my - ah employer.’ 

‘Your employer,’ Cleo said dubiously. 

‘Yes. We’re just - ’

‘Holding a business meeting?’ Cleo said sarcastically, and she reached into her bag to look for her phone. ‘I’m calling the police.’ 

‘Cleo - ’

‘No need,’ Kerr said, raising his hands. ‘I’ve made my point. Sutherland, you’d better resume sending regular reports, or I’ll have to take more serious steps.’ 

‘I - yes, of course,’ Owen said, looking thoroughly discomfited.

‘Well then, I’ll leave you to your brave defender,’ Kerr said, shaking his head, then he turned away and disappeared back into the trees. 

Cleo made a face at his retreating figure. ‘Your employer? Seriously?’

 ‘Don’t ask. You shouldn’t get mixed up in this.’ 

Cleo glared at him. Being treated like a child was nothing new to her: she’d spent years cycling through short hair, dyed hair, piercings, black coats, ripped jeans, and obscene T-shirts, but nothing had ever succeeded in offsetting the way she looked, this frail, insubstantial sort of prettiness that made everyone she encountered want to coddle and protect her. 

That didn’t mean she was resigned to it, though. ‘Fine,’ she snapped. ‘I won’t bother next time.’ And she set off up the hill toward the Tivoli Royale. 

Owen and Cleo had parted coldly in the lobby of the hotel, and Cleo had gone straight to bed to sleep off the effects of the whisky. Fortunately she had only a slight hangover this morning; an aspirin or two put paid to that, but the memory of last night’s events was not so easily shaken off. What exactly had Owen said to Kerr? Something about Elsinore? She knew the name from Hamlet, but somehow she doubted that Owen and Kerr had been discussing Shakespeare. 

Getting out her laptop, she went online and searched for ‘Elsinore + quantum computer,’ and got a long list of results, all of which seemed to be connected to a company named Elsinore Instruments, an international manufacturer of scientific instruments with headquarters in Copenhagen; apparently they had a quantum computing division, though she had no idea what that meant. 

She sat back, frowning at the screen. She felt certain that Owen and Kerr were involved in something shady, and she also knew that it would just keep nagging at her if she didn’t find out what was going on. Besides, she was alone and unoccupied in Copenhagen, and for the first time in her life she could afford to indulge her curiosity. Owen’s warning still rang in her ears - You shouldn’t get mixed up in this - but that only made her more determined. She had never reacted well to being told what to do, and after everything that had happened to her, what had once been a low-level, quiet, simmering rage had risen much closer to the surface.

***

When Mark arrived at Leith Investigations on Friday morning, Evelyn Leith herself was waiting for him. 

She took one look at his face and sighed. ‘Why do you even bother coming in when you’re barely awake? Come on. Get yourself a stronger coffee and meet me in my office.’

Mark resented this attitude – it cost him no small effort to get himself up and into the office on time every day, and besides, he had already consumed quite a lot of strong coffee this morning. Nonetheless, he dumped several spoonfuls of instant into a mug of hot water and took a fortifying gulp, then drew himself up as best he could and went in to face his employer. 

Her office was a sparse, professional space, furnished like a prison visitation room, and decorated only by framed copies of forged documents that Ms Leith had identified over the course of her career – the study and detection of forgery being, as far as Mark knew, Evelyn Leith’s sole passion in life. It also smelt of microwaved chicken soup, because Ms Leith seemed to work almost twenty-four/seven and ate most of her meals at her desk. Wishing devoutly to be elsewhere, Mark lowered himself into the chair in front of her desk and did his best to look more awake. ‘Is this about the Parker case?’ he asked. ‘Like I said in my report, I think they’re wasting our time. Charge them as much as possible and then get rid of them.’  

‘Already done,’ she said dismissively. ‘No, this is something new. I’ve had an unusual request – from Copenhagen, of all places.’  

 ‘Copenhagen?’ Mark stared at her. ‘You mean the one in Denmark?’ 

‘Come on, Mark, there’s only one Copenhagen. Can’t you at least pretend to be capable of intelligent thought?’

‘But why is someone from Copenhagen writing to us?’ 

‘Because they want us to send an agent over there.’  

Mark frowned. ‘They must have PIs of their own in Denmark.’ 

‘I imagine so – but they don’t just want any PI. They specifically want you.’ 

Mark paused. ‘Me,’ he said without intonation. ‘They want me.’ 

‘Let me explain. The contact came from a company called Elsinore Instruments – I’m sure you’ve heard of them.’  

‘Of course. They’re a big deal in the world of experimental science.’

‘Well, someone called this morning from their headquarters in Copenhagen. They’re in need of a PI, and they want someone who knows about quantum physics.’

‘Ah,’ said Mark. ‘Yes. I guess I can see how that would have narrowed their options down a fair bit.’ 

‘They’re willing to pay three times our usual rate – much of which would be passed on to you, of course.’ 

‘You don’t have to sell it to me. I’ll go. I’ve never been to Copenhagen.’ 

‘Really? Well, I’ve heard it’s supposed to be pretty.’ But Ms Leith’s tone that left little doubt as to her opinion of cities that were pretty.  

‘What’s the case?’ Mark asked. ‘Tell me it’s not financial fraud again.’ 

‘Actually, they wouldn’t say. This is all very hush-hush – you’ll be asked to sign a non-disclosure agreement, all the usual rigmarole.’

 ‘You think they’re involved in something illegal?’

‘Quite possibly. Don’t worry, you retain the right to refuse the case if you don’t like the sound of it. But I don’t want you to do that unless there’s really no other option.’ 

‘That’s fine. I know the drill.’  

‘Good. You fly out tonight, leaving 5pm from Heathrow – I’ll send you the details. Give Lizzie a quick briefing on your open files, then go home and pack. I expect to see you back here in a week with a nice fat bonus.’ 

Thus dismissed, Mark returned to his desk and began trying to sort his files into some kind of order, though he was already beginning to regret agreeing so quickly to go to Denmark. A free trip to Copenhagen was all very well, but he was not keen on working at a physics institute – he had not been back inside one since the scandal that had ended his career, and he suspected that this trip would open all sorts of old wounds for him.

For a moment as he stood there, he was overwhelmed by a resurgence of the old bitterness. Always at these times he found himself remembering the long, lonely years of his adolescence, which he had been able to endure only by telling himself that if he studied hard enough, one day he would find his way into a community where he belonged. He had worked single-mindedly, had made all the appropriate sacrifices, and for a few wonderful years he really believed he had arrived. The conferences, the quiet camaraderie, the geeky jokes: all signs, he had thought, that these people were coming to like him, trust him, respect him. 

So it was all the more devastating when his community turned on him. 

Over and over again he insisted that he had known nothing, but no one believed him: not his university, not his parents, not even his girlfriend. And in a matter of weeks his whole future had fallen to pieces. He wouldn’t be able to get an academic position without a PhD, and in any case he could not forgive academia for what it had done to him. He tried applying for jobs in finance, but found he couldn’t compete with his peers who had managed to complete their degrees before absconding. And he certainly wasn’t inclined to teach physics in high school – he wasn’t going to guide more unsuspecting young people into the field which had betrayed him. 

So he found himself scrolling dispiritedly through hundreds of pages of online job advertisements. In the miasma of corporate jargon, the entry for Leith Investigations caught his eye mainly because the job title actually meant something and the job description did not use any of the words ‘prestigious,’ ‘integrated,’ or ‘team’. He sent in a copy of his CV, and was mildly surprised to be offered an interview the following week with Evelyn Leith herself, who turned out to be a small, faded woman with inexpertly dyed reddish-brown hair and age lines that had not yet softened into gentleness. But though she looked as if she existed merely to serve as the butt of jokes about middle-aged female drivers, that impression was dispelled as soon as she opened her mouth, addressing him in the clipped, impatient tones of one comfortable with authority.  

 ‘Why didn’t you finish your PhD?’ was her first question. 

Mark was resigned to the fact that any potential employer would demand this explanation, but he never enjoyed giving it.  

‘Some people at the lab where I worked were caught falsifying results,’ he explained. ‘The university ruled that my work was invalidated as well, even though my results were genuine.’  

 ‘Did you know what was going on?’  

‘No,’ he said immediately. 

‘Hmmm. So you expect me to believe you’d be a good PI even though you spent four years working next to criminal activity without noticing a thing.’  

Mark blinked. ‘I – ah – I hadn’t thought about it that way.’

‘Well perhaps you should have,’ she said, moving to file his CV away. 

In her mind, no doubt, the interview was at an end, but Mark had not dragged himself out of bed this early just to be sent away after a single question. ‘Look,’ he said. ‘I didn’t notice what was going on because I was focused on my work. Which I was good at. If I focused on looking for criminal activity, I’d be good at that too.’ 

Ms Leith pursed her lips. ‘You’re sure of yourself.’ 

‘I’ve always been able to do what I set my mind to. I’ll be able to do this.’ 

‘So you say.’ She appeared to waver, then looked back down at the CV. 

 ‘Do you read detective novels?’ she said abruptly. ‘Or watch TV crime dramas?’ 

‘I haven’t had much time to read anything for the last four years. Not much time for TV either. But I can certainly start reading detective novels if you think that’s desirable.’ 

‘It’s not. Most of the people I interview fancy themselves as the next Hercule Poirot. They’re soon disappointed. We don’t do divorce work, but we take pretty much anything else, and I can promise you it’s seldom heroic or exciting. Mostly just background checks and reading financial records.’ 

‘I’m not here for excitement.’  

‘Then why?’ 

Because I need some kind of job, obviously. Mark swallowed that answer and gave the reply he had prepared. ‘I used to be a scientist, and I’ve always enjoyed solving problems, even ones that other people think are dull. I think I would find this job interesting, and I believe I would be good at it.’  

Ms Leith peered suspiciously at him, as if she suspected him of insincerity. But really, thought Mark, did anyone really expect sincerity in a job interview? He attempted to meet her gaze with an expression of absolute self-confidence, and eventually she said coolly, ‘Fine. I’ll hire you for a month’s probation and we’ll see how it goes.’

A month’s probation had turned into a six-month contract, then a year, and by now Mark had been a permanent employee of Leith Investigations for almost eight years. To match the job he had accumulated a battery of highbrow tastes – films by Bergman, books by Murakami – though he hadn’t been able to rid himself of a fondness for American country music, and, when drunk, could sometimes be convinced to perform his favourite numbers with unexpected tunefulness. But the rest of the time he stuck to a tragic demeanour: with his dark hair, long narrow face, and pronounced cheekbones, he wore a brooding expression well, and it had become become so much a part of his persona that these days he hardly knew himself whether or not he was genuinely unhappy.

If nothing else, he thought to himself as he finished gathering his files, the trip to Copenhagen would provide him with the start of another good anecdote. Even if the case turned out to be uninteresting, he could always make up a better ending: he was already well accustomed to embroidering his stories when reality fell short. 

*** 

The way to Elsinore Laboratories lay through Norrebro, Copenhagen’s student quarter, and for a time as Cleo wandered toward her destination she felt almost carefree, almost happy. There was an exuberance about the brightly coloured walls and cartoonish graffiti, and though she couldn’t quite share in this feeling, she could at least witness it. 

But as soon as the silvery roofs of the laboratories became visible above the surrounding houses, she could tell that Elsinore’s headquarters would have nothing of the same warmth. The steel sliding doors and solar panels artfully incorporated into the lines of the structure might have been at home in New York or Chicago, but the building felt completely out of place in the overgrown village of Norrebro. 

After several minutes spent watching the steady trickle of people leaving Elsinore Laboratories  Cleo picked one small group and followed them back into Norrebro. As hoped, they led her straight to a nearby bar, a battered little place with a sign reading Kanal 27. Inside, the low rafters hummed with good cheer, and there was even a small fire complete with what looked like chestnuts turning on a spit. It was immediately clear this must be a regular watering hole for the students and younger researchers at Elsinore - the customers were overwhelmingly male, most dressed in polar fleeces or woolly jumpers that they had probably owned since the dawn of time, and Cleo saw at least three people scribbling numbers on a napkin. 

Squinting into the hazy light, she finally spotted a booth that wasn’t quite as full as the others. The three men occupying it looked to be around her own age, twenty-six, and given the male-to-female ratio in the room, Cleo doubted that they would object too strenuously to her presence. She began threading her way across the bar, searching her memory for the few fragments of Danish she had learned on the plane, and when she was close enough she cleared her throat and said politely, ‘Må jeg slutte sig til dig?’ May I join you? 

‘Selvfølgelig,’ said the nearest young man. 

Cleo had no idea what this word meant, but his expression looked like assent, so she took up a seat on one side of the booth. ‘Tak. Jeg er alene her,’ she pronounced carefully. Thank you. I’m alone here.  

The men exchanged glances. ‘We can speak English,’ said one of them, a broad-shouldered, ruddy-faced fellow with a dense thatch of blonde hair. ‘If you would prefer that.’ 

 ‘Thanks. As you can tell, my Danish isn’t great.’ 

A waitress appeared at the corner of the table, and Cleo asked for a scotch. She didn’t really like whisky all that much, but she did enjoy the mildly surprised looks people always gave her when she ordered it. 

‘I’m Cleo – I come from the US – from Colorado,’ she said, once the waitress had moved away.

‘I’m Jac,’ said the blonde one. ‘And these two are Roald and Olivier.’  

‘I’m guessing you’re all students? This seems like a student place.’ 

‘Jac’s still working on his PhD,’ said Roald. ‘Olivier and I are postdocs.’

Cleo cast a sideways glance at Olivier: despite his battered glasses and terrible haircut, he was undoubtedly the best-looking of the three. ‘Nice to meet you,’ she said.

‘Jac and I both work in quantum computing at Elsinore Instruments, just round the corner,’ Roald said. ‘And Olivier is at the Centre for Quantum Devices in the Niels Bohr Institute.’

Bingo, Cleo thought. She leaned forward to ask a question, but at that moment the waitress arrived bearing her drink, followed almost immediately by a girl in a bulky woollen sweater. She was almost as short as Cleo, with quietly intense eyes, and as she slid onto the bench beside Olivier she cast a slightly challenging look across the table at Cleo.  

‘Ah – this is my girlfriend Mayumi,’ Olivier said, sounding a little flustered. ‘Mayumi – Cleo.’

Cleo found this development mildly entertaining: evidently the three of them were not entirely without female acquaintances. ‘Nice to meet you,’ she said, smiling at Mayumi. ‘Are you a physicist too?’ 

Going by gender stereotypes, she was expecting a no, but Mayumi said, ‘I’m with the nuclear science group at Elsinore Instruments. And you?’ 

‘Couldn’t be further from it,’ said Cleo. ‘I’m in business.’ 

She was a little surprised that no one questioned this, but perhaps it was because she was dressed for the part. She had recently adopted a wardrobe of severe business suits, which were unflattering on her small frame, but did at least make her look a little closer to her actual age, to the extent that she had even been called a woman rather than a girl in more than one newspaper.

‘But my work is very boring,’ she added. ‘Yours sounds much more interesting. What exactly do you do with quantum computers?’ 

‘Well, nothing at the moment,’ said Jac. ‘No one’s actually built a working quantum computer yet, although there are quite a few research groups all over the world trying to do it. Everyone has different ideas about the best approach, so there’s a lot of competition.’  

 ‘Sort of a modern arms race,’ said Cleo.  

‘In a way, I guess, though I don’t think quantum computers will ever be used as weapons.’   

‘What will they be used for? They must do something pretty amazing if everyone’s so keen on making one.’ 

‘Well, they’ll be faster than ordinary computers.’

‘Is that all? I mean, computers are already pretty fast.’ 

‘This is on a whole different scale. There are tasks that quantum computers will be able to do in seconds which would take a conventional computer hundreds of thousands of years.’ 

Cleo blinked. ‘That’s - a pretty big difference.’ 

‘Exactly.’

‘But - what sort of tasks? Are they tasks that anyone actually wants done?’ 

‘Well, for example, you could use a quantum computer to get round the cryptographic systems that currently keep digital communications and transactions secure. Including everything that goes on in the world’s financial markets. So yes, I imagine someone does want that done.’ 

Cleo thought again of Owen Sutherland. Elsinore aren’t playing ball. What exactly had she stumbled into here?

‘That sounds problematic. Shouldn’t we all be getting worried?’ she asked. 

‘Well, people are busy developing new methods of cryptography that resist quantum attacks. But they’re more expensive, so no one’s likely to bother implementing them until there are real quantum computers up and running, and that seems a fair way off yet.’ 

He launched into a more detailed explanation of his field, joined enthusiastically by Roald and Olivier. Cleo listened in increasing bewilderment to their talk of particles that were also waves, spooky action at a distance, and things that could travel down two different paths at the same time. ‘I’m going to be honest,’ she said after a while. ‘I’m hearing what you’re saying, but I feel like I don’t understand a word.’ 

Olivier laughed. ‘Don’t worry. The truth is, no one understands it – not even the physicists.’ 

‘Feynman used to say that if you think you understand quantum mechanics, you don’t understand quantum mechanics,’ Roald added. 

‘Well, speaking for myself, I neither understand quantum mechanics nor even think that I understand it,’ said Cleo. 

 ‘I know the whole thing seems really weird and counterintuitive,’ Jac said. ‘But that’s kind of the point. It forces you to learn a whole new way of thinking about the world.’  

‘The way the universe works is extremely beautiful. We’re all very lucky that we get to study it,’ Mayumi said all of a sudden. It was almost her first contribution to the conversation. 

Cleo smiled diplomatically: she could not really bring herself to accept that it was a privilege to be allowed to spend your days doing maths. But she was nonetheless a little envious of these students, and indeed, of anyone who cared so deeply about ideas. She wished her own desires could be so simple.  

***

As the meeting began, night was folding gently over the city. The streets emptied of cars, the electric lights shut off one by one, and the buildings seemed to retreat further and further into their own past. Eventually the soft, billowing darkness smothered all sound and the centuries blurred into sleep. 

From above, Copenhagen did not look like a hub of scientific and technological innovation. It was the city of Hans Christian Andersen, the home of Europe’s oldest royal family, and even now it retained something of the fairy-tale about it. Yet beneath those cobblestoned streets were some of the world’s most advanced physics laboratories, where scientists regularly pulled apart the fabric of reality and performed feats that the world believed impossible. 

The people in this room understood the importance of what was going on far beneath them, and it was at the forefront of their minds as they took their seats at the table. There was no room for mistakes now. After months of effort everything was coming together, the culmination of their work tantalisingly near, and the room crackled with a sense of purpose so sharp it felt as though the air itself might ignite. 

But it was hard to ignore the view of Copenhagen spread out before them. The sight was a poignant reminder of what their success would cost: this had always been a city of dreams, a place of optimism and idealism, and it was really a great pity to think that within two weeks the city would be levelled to the ground and most of its five hundred thousand inhabitants would be dead.