Текст книги "Zodiac Station"

Автор книги: Tom Harper

сообщить о нарушении

Текущая страница: 18 (всего у книги 22 страниц)

Forty-three

Anderson’s Journal – Saturday

I feel like I’m living a double life. All around me, Zodiac goes on as normal. Through the mess windows, I can see the students decorating for Thing Night; Fridge tramps around base breaking ice off his instruments; Greta’s on the roof repairing storm damage. No doubt Danny’s cooking in the kitchen, and Quam’s flicking that executive toy on his desk. And me? I’m holed up in the Star Command caboose like a fugitive. I slept here last night, with a packing crate wedged against the door and a loaded rifle beside me. I wonder if anyone’s noticed.

Even with the heater on, the temperature in Star Command is touching zero. I’ve got Hagger’s samples in the fridge to keep them warm; I keep on expecting the thermal cycler and the mass spectrometer to pack up completely. I’ve had to insulate them with my jumpers so that I can get the samples hot enough to incubate. But I’m almost there.

The storm had died down this morning, but the wind was still rattling around the station. Even so, there was no mistaking the firm knock. I scraped frozen condensation off the porthole in the door and peered out. Greta stood there, in her pigtailed hat, holding a plate covered in foil.

‘Waffle day,’ she announced when I opened the door. ‘I brought you one.’

‘How did you know I was here?’

She uncovered the plate and handed me a fork from her pocket.

‘I hope you like syrup.’

Even the short journey from the Platform to the caboose had chilled it down. The waffle was flaccid and rubbery. Even so, I was more grateful to her than I knew how to say.

I poked my fork into the Z stamped into the waffle’s centre. ‘It looks like the mark of Zorro,’ I joked.

‘Yeah.’

Maybe they don’t have Zorro in Norway. She looked at the sleeping bag on the floor. I suppose she noticed the rifle, too.

‘Working hard?’

I had to tell someone or I’d go mad. ‘This is going to sound crazy, but I opened Martin’s email last night. I found a message from a colleague in England, someone who’d reviewed his results from the big Nature paper last year. He claimed Martin doped his samples.’ I explained about Pfu-87 polymerase. ‘It’s an enzyme to make the DNA in the water combine and evolve much faster than it would naturally.’

Greta shook her head. ‘Martin wouldn’t.’

‘I don’t think he did. He was as surprised as anyone. He knew there’d been trouble replicating his results. That’s why he came back here to overwinter.’

I unrolled the map where I’d marked his samples. ‘You can see what he was doing. All through the winter, collecting samples around Zodiac, trying and failing to replicate his own results. He didn’t understand why it wouldn’t work. That’s why he was so down.’

I moved my finger up to Echo Bay. ‘Then, in March, Quam sent him to help DAR-X with their leaky gas pipes. That was the breakthrough. Martin analysed the water there, and found it was bursting with these little organisms feeding on DAR-X’s pipes. I’m guessing that made him wonder how they could have evolved so quickly, and reproduced in such numbers. So he reran his original experiment using water from Echo Bay. Bingo.’

‘Are you sure?’

‘Martin’s original sample, for the Nature paper, came from a summer trip to Gemini.’ A shadow crossed Greta’s face. She must have been thinking how Hagger had kept warm at Gemini. ‘He went down to the Helbreensfjord and got a sample. Pure chance. When he came back this winter, he stayed close to base.’ She still looked sceptical. I pointed to the machine on the bench. ‘I’ve analysed all his samples. All the ones from between the Helbreensfjord and Echo Bay – the red dots on the map – contain high doses of this enzyme.’

‘OK,’ she said.

‘But that’s not the crazy bit.’

‘OK.’

‘My PhD was on polymerase enzymes – specifically, on Pfu-87.’

‘With Martin?’

‘A guy called Richie Pharaoh. I switched PhD supervisors after my first year.’ That was a story I didn’t want to go into. ‘The point is, Pfu is a naturally occurring enzyme. It was discovered in bacteria that live in volcanic vents on the ocean floor. But Pfu-87 is a synthetic variant, a version that’s been genetically tweaked in a lab to work better. It doesn’t occur in nature.’

I realised I’d begun to tremble.

‘And that’s the crazy bit? Because it’s man-made?’

‘The crazy bit’ – the reason I was holed up in the caboose with a gun – ‘is that I invented it. I made the modifications. That was my PhD, and the paper I published. Martin had a copy in his lab.’ And I’d thought he was just checking my credentials. ‘At least now I know why he brought me here.’

Greta thought about that. ‘So one question.’

‘Only one?’

‘Why is the Helbreen pumping out this DNA chemical you invented?’

I wished I had a good answer.

‘I have to go fix the satellite dish,’ she announced. ‘If we don’t get the Internet back, people will start eating each other.’

Her question echoed in my mind a long time after she’d gone. Why is the Helbreen pumping out this DNA chemical you invented?

Answer: It isn’t. I’ve tested all the samples Hagger took from the glacier three times over. No Pfu-87, from the top of the glacier down to the very front edge. Nothing until you get into the seawater below the ice. All green. As if it’s just welling out of the seabed.

I was still thinking about it an hour later when Eastman came through the door. No knock, and I’d forgotten to jam it shut after Greta left. My rifle was on the other side of the room.

He smiled that brilliant smile, though it didn’t have quite the same wattage. As if the bulb was going. His face was red, his eyes were bright and he spoke too quickly.

‘What’s going on?’

He was jumpy. Literally: he couldn’t stay still. If I’d been stood near him on the platform at Cambridge station, I’d have assumed he was a drug addict.

As blandly as possible, I told him I was working on Hagger’s old data.

‘I heard they were bullshit.’ Succinct as ever. I wished Kennedy hadn’t shown him the email.

I explained why I thought Hagger was innocent, leaving out the Pfu-87. Eastman didn’t seem to pay attention. His eyes were always moving, taking things in at a thousand frames a second.

‘What are those?’ he said, pointing to the machines.

I couldn’t tell if this was just a prelude to an act of violence. I mean, I’ve seen enough films where the psychopath makes conversation about cheeseburgers or parking wardens and then suddenly smashes his victim’s face in. I played along, and tried to edge around towards the rifle.

‘Do they work?’ he said.

‘Perfectly.’ I could almost reach the rifle, now. Eastman must have noticed. His arm suddenly shot out to block my way, thrusting a sheet of paper into my hands.

‘I got another reading on that interference.’ The paper was covered with noughts, ones and twos, the same as the one from Hagger’s notebook. ‘Looks like it’s coming from near Vitangelsk. Up by Mine Eight.’

He leaned very close to me as he said it, as if I was a pretty girl at a party. Like the girl, I couldn’t do anything except shrink against the wall, and wish I had my gun.

‘If only we could unlock it.’ Heavy emphasis; in case I missed it, he mimed turning a key with his hand. ‘You know, with a key.’

It wasn’t subtle. So I’d been right, the key must have been his – dropped where Hagger died. I tried not to show that I’d guessed. He’d kill me right there.

The sequencer beeped and broke the moment. The printer chattered, and a spool of paper came out. I tore it off and jammed it in my pocket before Eastman could get a look.

‘Have you ever been to New York?’ I asked, thinking of the bear on the key ring.

Thankfully, at that moment Kennedy came in and announced that Quam had gone to check one of the bear cameras. It must have meant something to Eastman. He left so quickly he forgot to take his paper.

* * *

As soon as he was out the door, I barricaded it with as many boxes as I could find. Which meant that when Greta arrived, five minutes later, I had to move them all over again. No waffles this time; she didn’t even ask about the elaborate barricade. Her face was red, almost as if she’d been crying.

She fell against me. I just caught her, holding her to my chest like a hurt child. Her body convulsed with silent, tearless sobs. I didn’t know what to do, except pat her on the back. Then, without thinking, I started to stroke her hair.

She pulled back from me as if I’d burned her.

‘Don’t—’

I held up my hands. ‘I’m not … I wasn’t …’ Took a step back. Asked, ludicrously, ‘Are you OK?’

She stalked across the room, head held so stiff you could have cracked bricks on it. Glanced at the readouts on the machines. She still looked as if she might burst into tears – or bite someone.

‘It’s nothing.’

‘Really?’

‘I had a bad experience.’

It’s the sort of statement that ties me in knots. I want to help, but I’m petrified of being thought intrusive. A very English problem. I’ve always envied the people who can just throw their arms around complete strangers without analysing it from twenty different angles.

‘Do you want to talk about it?’ I tried.

‘No.’ She flexed her fingers, as if imagining closing them around someone’s throat. ‘You know why I came here? To Utgard?’ I shook my head. ‘To get away from all the assholes.’

Something on the workbench caught her eye. She picked up one of the plastic bottles lying there, spun it in her fingers, then threw it against the wall like a fielder shying at the stumps. ‘Asshole.’

I looked at the empty bottle. I’d thought they were solutes for the machines, but now I read the label I saw it was something else. Rhodamine B hydrological dye. Caution: Stains.

There was only one person at Zodiac I knew who used that in her research – and Hagger was supposed to have broken it off with her months ago. No wonder Greta was furious.

Forty-four

Anderson’s Journal – Saturday

You’d think, with two dozen people confined to a few hundred square metres of ice, it would be easy to find anyone you wanted at Zodiac. It took me the best part of an hour to track Annabel down; eventually, I found her on a pair of skis gliding around the perimeter. I wondered if we’d been chasing each other round in circles all morning, like Pooh and Piglet.

‘I’ve been in the bang shop.’ She waved her pole at one of the older, wooden huts, where they keep the explosives. ‘Have you seen anyone go in there? Twenty kilos of det cord’s gone missing.’

‘Don’t look at me.’

‘No,’ she agreed, in a way that seemed to imply I wouldn’t be up to it. ‘Probably one of the American students who doesn’t understand the metric system.’

She pushed off and began to ski away. I followed.

‘I want to ask you about Martin.’

She didn’t slow down. I took the Rhodamine-B bottle out of my pocket and threw it in front of her. ‘What was he doing with that?’

‘You’ve just violated article nine of the Utgard Treaty,’ she told me. ‘Littering.’ She stopped, bent down and picked it up.

‘I found it in his lab. Half a dozen of them. I just want to know what you were doing there.’

‘He must have taken them from my store. I haven’t been in his lab in six months.’

‘Greta thinks you have.’

Wrong thing to say. She started skiing again; I had to run to keep up.

‘What was Martin doing with that dye? Did he come to you for help?’ I was starting to sweat. Lithe and long-legged, Annabel seemed to glide effortlessly over the snow. ‘You use Rhodamine to trace water in the ice, right? Was Hagger interested in something coming off the glacier in meltwater?’

She stopped and looked back. She wasn’t even breathing hard. ‘Be careful. Last time you and I went running around the ice together, you fell down a hole.’

‘Did Martin ask you about the glacier? Please,’ I added. A cramp was spreading through my side. I knelt down in the snow and pressed my hand on my knee. I probably looked ridiculous.

Annabel surveyed me, the Ice Queen looking down on her subject.

‘Hagger asked me about the ionic profile of some water samples. That’s all.’

‘What did you find?’

‘High sulphite levels.’

I struggled. Sulphite’s a mineral, nothing to do with enzymes and proteins. Nothing really to do with biology at all.

But Annabel was holding something back. Waiting for me, behind her mirrored glasses.

‘What do high sulphite levels mean?’

‘Glaciers don’t just push ice down to the sea. They’re complex hydrological systems with their own chemistry. Ice is an insulator; it sits on top of the rock like a heavy blanket. Now, the rock has heat in it from the earth’s core, and that heat can’t escape, so it melts the bottom of the glacier. The whole thing’s sitting on a water slide. As water flows through the channels, or over the rock, it gathers its own chemical signature. Chloride means it’s come from melted snow; calcite means it’s travelled under the glacier, in contact with the rock.’

‘And sulphite?’

‘Sulphite doesn’t show up in meltwater much.’

‘But you said—’

‘There are only a few places in the world where it happens, so we don’t have much data. But where there are mine workings that go underneath a glacier – and, as I said, that’s not common – we’ve seen evidence that the mines can become part of the glacier’s drainage system. Meltwater seeps into the tunnels, and then joins the glacier again and flows out at the bottom.’

‘And sulphite ions are evidence of that.’

She nodded. ‘Digging tunnels exposes the rock to air. The air oxidises the metals in the rock, which produces sulphite. Then water flows through and washes it out.’

I’ve got enough chemistry that I could follow that. ‘So Martin showed you some of his samples.’

‘Yes.’

‘And the sample bags – do you remember if they had coloured dots on them? Red or green?’

‘All the ones that tested positive for sulphite had red dots—’

‘You’re sure?’

In my eagerness, I’d jumped in too quickly and cut her off. She shot me a dirty look.

‘I asked him about the dots. I thought he might be playing a joke on me. But he said all the red ones came from the Helbreensfjord, which makes sense. All the mines around Vitangelsk – the tunnels go on for kilometres. Some must go right through the mountain and under the Helbreen.’

‘So Hagger’s samples from the Helbreensfjord – the red ones – contained water that had gone through these mine tunnels under the glacier and come out at the bottom.’

‘The data’s consistent with that hypothesis.’

‘And Rhodamine B would prove it. I mean, if you poured some of that dye in at the top of the Helbreen, and found it coming out at the bottom full of sulphites, that would be the proof.’

‘I’ve never put dye around there.’

‘But Hagger asked you to.’

‘It’s not in my project. And unlike some people, I do what my funding body are paying me to do. That’s why they keep funding me.’

I waved the dye bottle. ‘So he tried it himself.’

She sniffed. ‘Even if he did, he couldn’t have interpreted the data. Finding Rhodamine in the outlet water, after it’s travelled ten kilometres underground in who knows which direction, isn’t an easy thing. Hagger couldn’t even pour it straight. He had the dye all over his hands when he died.’

She pushed back a slender leg, then shot it forward to begin skiing away.

‘Still does, unless anyone’s cleaned him up.’

The cold store at Zodiac feels like a morgue at the best of times. Long racks filled with ice cores, steel boxes spiked with frost. The body at the end, wrapped in plastic sheeting, almost seemed natural. Almost.

I unwrapped the plastic and examined Hagger’s body. It didn’t bother me as much as I’d thought: the flesh was frozen so hard, I couldn’t think of it as ever having been alive. As Annabel had said, a pinkish dye stained the hands, like a child who’d been overenthusiastic with the felt tips.

Was Hagger really so inept he spilled it all over himself?

I thought I heard a noise behind me and looked round. Nothing there, except the endless rows of ice cores.

The cores sample every snowfall that’s ever happened on this glacier, one on top of the other. You can read them like tree rings.

Hagger had an ice core in his freezer, I remembered. I’d wondered, when I saw it, why a man who studied sea ice would care about the lifeless heart of a glacier. I’d also wondered how he came by it.

The whole thing’s sitting on a water slide.

What if it wasn’t what’s in the ice that interested him?

I ran back to the Platform. Ignoring the party in the mess, I dived into Hagger’s lab and opened the fridge. I’d forgotten the freezer compartment when I’d cleared out the samples, but it was still there: a stubby cylinder of ice that looked as if it had been chopped with an axe.

I took it back to the caboose and put it on the hot plate. Usually, you use the hot plate to break down DNA, but it worked pretty well as a stove. In a few minutes, the core was sinking into a puddle of its own meltwater. I poured it off into a beaker, prepared a solution and ran it through the mass spectrometer.

The graph matched the others perfectly. A bit weaker, but that was understandable: the contaminated water wasn’t part of the glacier, but had flowed under it. The trace must be from residue that had stuck to the bottom.

The enzymes aren’t in the glacier – they’re under it.

I’m lying on my bed catching up my diary. So much work, but I’ve got almost all of it now. Time to lay it out for myself.

Meltwater → under the Helbreen → mine tunnels → Helbreensfjord → ocean current → Echo Bay

Contains Pfu-87 enzyme, turbocharging food chain along coast

Algae → plankton→ fish → seals → bears

Accelerated evolution of Gelidibacter incognita bugs

Contamination of Hagger’s original samples

WHERE IS Pfu-87 COMING FROM?

→ not from snow/ice accumulation – glacier samples negative

MUST BE PICKED UP IN THE MINE TUNNELS

Eastman must know. All those loaded comments this morning about Vitangelsk, Mine 8. He was testing me to see how far I’ve got.

If he reads this, he’ll kill me.

Still not clear why he gave me the paper with those numbers on it. Some sort of test? Connected with Pfu-87 enzymes?

If there were four numbers, it would make sense. Could be DNA sequence, 0 = G, 1 = C, etc. Be interesting to compare with DNA coded by enzymes.

Unless …

Pharaoh String! Is that why Hagger brought me here? Impossible.

Noise outside – someone coming.

I have to get to the Helbreen right now.

Forty-five

USCGC Terra Nova

Franklin put down the journal as Santiago came in to his cabin. Kennedy was with him, leaning on a crutch. His bandages had come off.

‘We took a look at the guys from the tent,’ Santiago said. He looked angry about something. ‘Tell the Captain what you told me.’

Kennedy licked his lips. ‘The man you found out there – it’s Tom Anderson.’

‘I told him it can’t be. Tom Anderson’s got six inches and about eighty pounds on this guy.’

Kennedy looked irritated. ‘I think you can trust me to recognise him.’

Franklin closed the book. ‘Is he going to wake up so he can tell us himself?’

‘Doc says fifty-fifty. He was out there a few days. The woman, Greta, she’s in better shape. Doc thinks she arrived later, probably came to rescue him but ran out of gas. She must have let off the emergency beacon. Had it tucked up with her in the sleeping bag, to keep the batteries warm.’

A wistful look came over him. ‘Be nice to have a chick to curl up in a sleeping bag with me out here.’

‘Mrs Santiago would hate to hear you say that, Ops.’

‘Mrs Santiago hates the cold.’

Franklin reopened the book. Santiago didn’t take the hint.

‘Something on your mind, Ops?’

‘Just wondering, sir. If we do have Anderson, who the hell did we have before?’

Anderson’s Journal – Tuesday (?)

I don’t know where to start. Don’t even know what day it is. After what’s happened … If I can’t make sense of it, how can I write it down?

At least I’ve got the rest of my life to think about it.

But that isn’t long. In this cold, life expectancy’s measured in hours. All that stands between me and the Arctic is a canvas wall. All that’s heating the tent is my own body. I can already feel it failing.

I read a story, before I came, how a nineteenth-century ship sank near the Bering Strait. Months later, wreckage arrived off the coast of Greenland, carried thousands of miles by the ice. Maybe one day this journal will land in Canada or Alaska, and a cruise-ship tourist will pick it up off the beach. They’ll wonder who I was, if this could possibly be true.

More likely, this flimsy piece of ice will spin off into open water and melt, until the ice gives and drowns the journal. Then all that’ll be left of me is a few drops of DNA in the ocean.

I miss Luke. Dying doesn’t frighten me on my own account – I’m not religious – but the thought of leaving him alone, and being without him, is making these last few hours a living hell. The best I can hope for, now, is that the ice holds long enough; that someone finds my body; that Luke can know the truth.

This is what happened.

I was on my bunk, staring at the sheet of paper with those noughts and ones and twos that I finally understood, when Greta came in.

‘Thing Night,’ she said. ‘You’re missing it.’

I swung myself off the bunk. ‘I have to get up to the Helbreen. Right now.’

She tilted her head five degrees to one side. That was about as surprised as she ever gets.

‘I know what Martin found up there.’

‘OK.’

‘We’ll need climbing harnesses and head torches.’

‘OK.’

We dressed for the cold. I could hear film music coming through the mess door, laughter and toasts, but they might as well have been on another planet. Greta fetched the climbing gear while I grabbed Hagger’s lab book and the journal with my notes. Luke’s Father Christmas letter peeked out of it, still undelivered.

I stood in the lab for the last time, and looked around. I had that feeling you get leaving for the airport, convinced there’s some vital thing you’ve forgotten to pack. But I didn’t dare wait any longer.

We left the Platform and headed for the snowmobile park. Just as we got there, a figure rose up from where he’d been crouching behind one of the machines. I was so keyed up, I almost shot him.

It was only Quam. He looked distracted; his hands were sticky, and he stank of petrol. Why he had chosen that moment for a spot of maintenance, I couldn’t think.

‘You’re missing Thing Night.’ He looked down, fiddling with his hands as if he’d spilled something on his glove. He sounded almost drunk.

‘So are you.’

‘Checking the fuel lines,’ he muttered. Greta gave him a sharp look.

‘Is something wrong?’

Quam shook his head. ‘Just checking.’

I could tell she didn’t believe him. I thought it was strange, too, but I had to be away. I grabbed her arm and tugged her towards the mag hut. ‘The reading,’ I said loudly.

Greta gave the snowmobiles one more unhappy look. She pointed to the flare pistol holstered on Quam’s hip. ‘Be careful with that thing.’

Quam covered it with his hand. ‘Be careful,’ he repeated.

He sounded dazed, like a zombie. If I’d only taken a moment to think about it, I might have put a few things together: the flare gun, the smell of petrol, the unlikely preoccupation with snowmobile maintenance. But the only exact science is hindsight.

‘What now?’ I asked, as soon as Quam was behind us.

‘The Sno-Cat.’

‘Won’t Quam stop us?’ Officially, we were still confined to base.

Greta shrugged. ‘Maybe.’

The Sno-Cat was parked behind the machine shop. Greta unplugged the umbilical cord that kept the battery warm, and started the engine. The moment it roared into life, I knew we weren’t going to get away unnoticed. The Sno-Cat’s not made for subtlety, or for speed. Sure enough, as we crossed the flag line I looked out the back window and saw Quam running after us, arms and legs flailing like a puppet with a broken string. For a moment, I thought he might even catch us. But you can’t run far in the Arctic. He pulled up suddenly, shouted something I couldn’t hear, then turned away. My last view was of him trudging back towards the Platform, shoulders stooped and head down. I kept watching, waiting for him to reappear with a snowmobile, but he never came.

I pitied Quam, then. I hoped he wouldn’t get into trouble on account of what Greta and I were doing. Of course, if I’d known what he was about to do, I would have turned the Sno-Cat around and put a bullet in his heart myself.

* * *

We crunched up the glacier and Zodiac disappeared behind us. In the tiny cab, there wasn’t much between us: every time Greta changed gear, or turned the wheel, I felt the point of her elbow. At least we weren’t cold, with the machine’s heater built from an age before oil shocks and global warming. I unzipped my coat.

‘Aren’t you curious why we’re doing this?’

She swerved the Sno-Cat around some obstacle I didn’t see.

‘Tell me.’

I explained my hypothesis, how the enzymes were running under the glacier and out into the sea through the mines.

‘The mines are sealed with concrete,’ she pointed out.

‘Water can get in through microscopic cracks.’

‘But how do we get in?’

‘I think Hagger found a way. He used Annabel’s Rhodamine dye to track the water flow under the glacier; he had it on his hands when he died. He must have followed the dye down one of the tunnels …’

‘Moulins,’ Greta corrected me.

‘… and found where the enzymes were coming from.’

A pause. ‘What’s an enzyme?’

I’d spent the last three days thinking about nothing else; the question threw me. But of course, why should she know? I thought for a moment. The throwaway answer wouldn’t do.

‘How much do you know about DNA?’

‘Some.’

Last year, Luke’s school invited me to give a talk about genetics to his Year 3 class. I fell back on that and hoped I didn’t sound patronising.

‘Imagine the human genome like a tower made of Lego bricks. The bricks can only be one of four colours, and the tower is three billion bricks tall. The bricks are stacked in pairs – so six billion in total – but there are certain rules. A red brick always goes next to a white one, and green always next to blue.’

‘OK.’

‘Each pair of bricks is what we call a “base pair”. In reality, the different coloured blocks are amino acids, four chemicals known by their initials G, C, T and A. To “read” the genome – sequence it – you just have to write down all those letters in the right order.’

I glanced across at her. ‘Still with me?’

‘Keeping up.’

‘Now, DNA makes RNA, which is like a copy of that Lego tower but only one block wide. RNA makes molecules called proteins, and proteins – among other things – make enzymes. An enzyme is a tiny biological machine, made of proteins, that performs a specific task. Like a little mobile chemical lab. It can be as fundamental as making your muscles move, and as mundane as breaking down stains on your laundry. You probably have them in your washing powder.’

‘I use non-bio.’

‘If DNA is the operating system of life, enzymes are the apps. The enzyme Martin found coming off the Helbreen is one that’s been created in a laboratory, for making DNA. Put it in a solution with the four bases, and it’ll grab them one after the other and stitch them together.’ I thought of Luke’s bedroom at home. ‘Remember my Lego analogy? Imagine you’ve got Lego bricks scattered all over the floor. The enzyme is like a little robot that can grab them one at a time, and snap them together in a preset order.’

Greta drove on. With the clouds low, it was dark enough that I could see the headlights roaming over the snow in front of us.

‘That’s why we’re going to the glacier?’

‘There’s something else.’ I got out the piece of paper covered in numbers. ‘Eastman intercepted these numbers being transmitted somewhere near Vitangelsk.’

She crunched into the next gear as if she was trying to decapitate it.

‘I know what the numbers mean.’

She didn’t look as impressed as I’d hoped. ‘Is it the password to get into the mine?’

‘It comes back to DNA. You see, the biggest problem with sequencing DNA isn’t the technology, or the process. That hasn’t changed much in thirty years, except to get quicker and cheaper. But each individual’s DNA contains three billion base pairs – that’s three billion pieces of information. And if you’re going to make use of it, you have to store it accurately and be able to retrieve it. Even one mistake, out of three billion, could mean the difference between perfect health and an incurable disease.

‘And the actual sequence makes mistakes too easy. In the genome, there are long stretches where the same base pairs, or pattern of bases, repeat themselves. Coming back to the tower, it’s as if you’re told to put 297 red bricks in a row. Very easy to miscount.

‘The man I did my doctorate with – Richie Pharaoh – he was obsessed with this problem. Any time you sequence DNA, you’re working with margins of error. You have to decide what you think’s acceptable. When the original Human Genome Project announced to the world that they’d sequenced the whole human genome – the articles in Nature and Time, the TV fanfare, the ceremony with Bill Clinton – what they didn’t say is that one in ten thousand of the base pairs was probably wrong. That was the margin of error they’d agreed on.

‘Now, one in ten thousand probably sounds pretty good. But with three billion base pairs, that’s still three hundred thousand mistakes – and it only takes one to ruin someone’s life. And there are two ways errors can creep in. Either when you’re reading the sequence, or when you’re writing it down. Which, practically, means on a computer.

‘So Richie Pharaoh devised a solution. Instead of standard binary code, the noughts and ones, where the same number always stands for the same base letter, he created a more advanced code where there are three numbers – zero, one and two – but each one records a different value depending on what went before it. Sort of like the Enigma machine in the Second World War, where the next letter changed depending on what letter you’d just typed.’

The system was pure Richie. Subtle and slippery, a solution to a problem most people, even leaders in the field, hadn’t realised existed yet.

Greta looked mystified. ‘Is this going to be on the test?’

‘The point is, Pharaoh never published it and it never caught on. Scientists were happy with the fiction that they’d “done it”, the software got better at correcting errors, and every time he tried to explain it to someone, their eyes glazed over. No one used it – except Richie Pharaoh. He always used it for his own experiments.’