When it was cool enough, the door was opened from the inside. The workers there threw out singed sandbags, which they’d evidently been using to seal the door, and made a run for it.

By the time they were gone, Debbie was vomiting. But still she held onto the hose.

The ground shuddered.

Earth tremor?

She wondered if that was what had triggered the explosion. She knew the two reactors here were cooled by pumped carbon dioxide gas. What would happen if a tremor knocked out the coolant pumps, or broke a feed line, or…?

Really, she knew nothing about nuclear plants. Nothing, except that you shouldn’t go near one at the best of times. And this was not the best of times.

When the maintenance guys were out, under the leader’s gestured command, the fire crew dropped the hose and ran towards the centre of the blaze. Debbie followed.

Her vomiting was over, but she was still dry-retching even as she ran.

There were fires everywhere. It looked to Debbie as if the stuff raining down from the central explosion — the reactor? — had ignited whatever it could find, like the tar on the roofs. She had some breathing apparatus now, dropped by an injured firefighter, but as they worked to the centre of the complex she found it progressively more difficult to battle through the intense heat, the acrid air, the molten tar which stuck to her boots, a black graphite dust which seemed to be everywhere.

She felt hot, inside and outside, a feeling she’d never known before.

They were met by a man in shirtsleeves and a Scottish Nuclear tie. He was the deputy station manager; he was wearing a badge that turned out to be a radiation dosimeter. His boss, the station manager, wasn’t here; she was crowning the Gala Queen in Dunbar five miles away. Local-friendly PR for the area’s biggest employer.

Gradually, as the deputy manager and the fire chief argued about what to do, Debbie figured out what had happened here.

“We’re protected from quakes here. The founds go down to bedrock. But we’re designed to withstand only up to a certain Richter. When the big tremor hit, the sea water conduits cracked…”

“What does that mean?”

The manager struggled to explain. “The reactors are cooled by carbon dioxide gas. The hot gas is passed through a boiler that turns water to steam, and the steam runs the turbine. The steam is in a closed loop. It passes through a condenser, where it’s cooled by sea water.”

“What happens to the sea water?”

“It’s dumped back in the ocean. The radiation levels are low, and we monitor—”

“Never mind that. So without the sea water flow there’s no way for heat to get out of the system?”

“And on top of that we had a total loss of power. The cee-oh-two pumps failed—”

“Shit, man, you must have backups.”

“Oh, yeah. We draw power from the National Grid to keep the coolant pumps going. And failing that we have eight diesel generators on site. But the quake was too severe. We lost everything. Even so there are failsafes. When the power failed, the damper rods should have fallen into the reactor cores by gravity.”

“Don’t tell me. They didn’t.”

“The core was distorted. We couldn’t get the rods in. And we had carbon dioxide trapped in the core because the pumps had failed, and the gas got hotter and hotter, until there was an explosion that disrupted the pressure vessel—”

“Hold it. What exploded?”

“Reactor Number One.”

“Oh, Jesus…”

There was a small fire team here, Debbie learned, but only one of them had worked for the Fire Service.

There were two nurses on site. Nobody knew where they were.

The chief was still arguing what to do with the station manager when the one experienced firefighter tapped a couple of buddies on the shoulder, pointed, and ran towards the big central building, which was still burning.

Debbie hesitated for one second, then followed.

The leader took the crew up an appliance ladder to the roof of a building which, Debbie learned, was the turbine hall. Here, a couple of crews were already plying hoses onto the burning building below.

It looked — to Debbie, in her ignorance — like the central reactor hall itself.

The central building was just a shell of metal and glass, pretty much blown apart, a shell that had been wrapped around a massive concrete cube: the reactor block.

She was looking down at the roof of the block, which was littered with equipment and protective clothing, hastily abandoned. There were three big discs of black tiles, set in the block roof. The centremost of these covered a store for spent fuel, and the two others were the two reactors themselves, in their forty-feet-high pressure vessels of concrete and steel, buried inside the block.

There was a huge lime-green crane-like machine which ran on rails along the roof; this was the fuel charging machine, designed to lug seventy-feet-long fuel assemblies to and from the reactor cores. But the charging machine was crippled, its iron frame bent out of skew.

Number Two Reactor, to her right, looked intact. It was Number One which had suffered the explosion.

Its massive lid had been blasted off — black tiles were scattered around the building — and its concrete shell was broken outwards, reinforcing bars flailing upwards wildly. She could actually see into the heart of the reactor, the exposed core, which was a mass of flame and smoke.

The firefighters were hesitating before this, arguing about what to do.

To Debbie it was obvious. The fire in that reactor core had to be put out, before any more radioactive products were vented into the atmosphere.

And there was only herself and the other firefighters to do it, by hand if necessary.

She’d heard about Chernobyl, the heroism of the firefighters there. The casualty rate later.

She’d never expected to encounter such a situation herself.

When she looked into the exposed core, she felt its warmth, on her face and chest and legs. She wondered if she ought to ask for a dosimeter badge.

She fixed her helmet and oxygen mask. With the others, she pushed forward, into the heat.

The traffic crawled through Dunbar, and beyond.

Further east, there was something going on. Jane could see a pillar of smoke, blowing inland. Helicopters were flapping over, dumping tons of what looked like sand.

Five miles past Dunbar, close to the source of all the smoke, somebody came blundering into the road in front of her, and Jane braked sharply. It was a fireman — no, a woman — singed donkey jacket, blackened hair, what looked like a bad case of sun-tan darkening her skin. She looked around blearily, focused on Jane, and came staggering to the passenger door.

“Please,” she said. “Help me.” Her voice was a hissed whisper.

She was just a kid.

Jane nodded. She got out of the car, and bundled the firefighter into the back. The woman lay down, her legs drawn up to her chest, shivering. Her face looked swollen, and she seemed to be trying to protect her hands. Around her neck, her skin had burst and was hanging in strips. She was bleeding through her nose, perhaps haemorrhaging. There was a name badge on her jacket. STURROCK.

Jack just stared.

Jane realized where she was. Torness. Jesus. I should have thought of this. I have to get Jack out of here—

There was a thunderous roar overhead, startling Jane enough to make her brake. “Jesus Christ. What now?”

She looked out of the window. Planes: fleets of them, huge black shapes, sweeping in from the north.

“They’re coming from RAF Leuchars,” Jack said.

Jane stared at him. It was the longest sentence he’d uttered in days.

“There are Vulcans. See, the British ones. And B-2As. The Americans. Look, that’s a B-52. And I think that’s a Tupolev, the white one. Russian…”