Maddy cursed herself for not seeing the problem earlier. It was so obvious, yet so devastating in its finality. She looked out at the small girl standing patiently next to the ship. There was no time now for keeping the truth from her.

'There's no airlock on this ship,' said Maddy. The tiny cabin reverberated with her words. 'And I don't have a space helmet.'

There'd been no time to grab one in the fight, no time to ponder the details of Geranium's rescue, to think of finding a helmet. And now it was no rescue at all. The dinghy was designed for simple transport, not complex rescue operations. There was simply no room in the tiny boat for luxuries like airlocks.

There was only one thing to do. Already Geranium's form appeared brighter, the shadow she cast darker as more of the Earth rose above the horizon. The planet was huge now, no longer a planet but a living world of people. Only one thing to do, and no time to bother with the details.

'I'm going to open the hatch,' she said. 'I'll just have to hold my breath. I can survive a few seconds like that.'

The girl started to protest. Maddy cut her off. 'No! Listen! This is important! You have to get in as fast as possible, as soon as the hatch opens. It's small so you'll have to come in head first. Tuck your legs in after you. Don't worry about finesse, just get in. And here's the thing—I might lose consciousness or be unable to do anything. The AI won't close the hatch by itself, it can't see when you're completely inside. You'll have to close the hatch manually. The lock is a handle on the right side of the door. It's big and red so you can't miss it.'

There was a pause, then Geranium said, 'What about the air? It'll escape.'

'I'm going to create a vacuum inside, store the air. That's what they normally do, make the whole ship an airlock. But usually everyone's wearing space suits. I'm going to instruct the AI to refill the cabin once the hatch is closed.'

'All right.'

At last she was ready. Maddy tucked her body back into the furthest corner away from the hatch so as to give Geranium as much room to manoeuvre as possible. Then she told the AI to remove the air.

As the air was sucked out Maddy emptied her lungs. Her ears popped but she stared fixedly at the hatch. As the last air was removed the pitch of the flowing gas rose, until it faded away into silence. There was nothing at all around her. She clung desperately to consciousness. In her mouth was the bizarre sensation of the moisture on her tongue beginning to boil.

The hatch swung open. The form of Geranium appeared, scrambling inside. Maddy wished she hadn't enforced the need for as much haste as possible now, the girl was moving so quickly she might compromise her suit and that would be the end of her. In a few seconds she'd climbed in, tumbling onto her back as she pulled her legs inside. She twisted around and leaned out to swing the hatch closed, then groped for the red handle. As soon as it engaged the AI's routine clicked in and there came the roar of returning air. Maddy drew in a huge breath.

Geranium clutched at her, pulled her tightly against her body. Maddy reached out and hugged the girl back. But in a few seconds she'd pushed her away again.

'AI! Launch. Take us away from the asteroid.'

Both women were pressed into their seats as the dinghy lifted off, its single lifter pressing hard against the surface of Shiva.

The ship streaked away from the asteroid as its barrelling pear-shaped form tumbled through space. At the far end, the engines installed by the crew of the Shepherd Moon were still firing.

Geranium pulled off her helmet and lay curled up like a baby in her seat. Maddy sucked in air for a moment and checked that the atmosphere was back to normal. The cold that had cut through the cabin when the hatch had been opened still lingered, but she hesitated to turn the cabin heat up: she wasn't sure how much power remained in the dinghy.

'What happened?' Geranium's voice broke a long silence.

'They died.' That was all she could say. 'Reed. Marshall. The Helots. Forget them. Are you all right?' Maddy opened a compartment between the seats. There was a small supply of snacks and some water. She couldn't stomach the food, but drank half the water and handed the rest to Geranium.

'There was a Serf,' the girl said. 'He came into the ship. He...'

Maddy had seen a crumpled red form beside the doorway of the ship on the surface. Perhaps this wasn't the right time for either of them to tell their stories in full.

'What happens now?' Geranium put a hand on the window where Shiva could be seen hurtling down towards the Earth. 'Is it going to hit?'

The Earth was gigantic in the window now, blue and white and brown. The last time it would look like that for a long age.

'Nothing we can do,' said Maddy softly.

'What! No! There must be...'

And in that moment, like the mighty fist of an avenging god, Shiva struck the Earth.

The cradle of civilization became its deathbed.

The eastern Mediterranean became as bright as the Sun, illuminating the dark side of the planet as if it were daylight. For a moment Maddy and Geranium had to shut their eyes until the flash had died and the heat spread out to scorch half the globe. When they looked again the Mediterranean Sea had vanished, that part struck by the asteroid exploding into steam as Shiva itself vaporised.

Maddy watched wide-eyed, staring, hand pressed against the dinghy's window.

I failed. I should have fought harder on the ship. Rix was dead. I could have found a way...I abandoned those billions of people down there. I—

She felt Geranium's hand grip hers.

I saved Geranium. At least I did that.

She squeezed the girl's hand so tight it hurt, but neither of them let go.

Another fierce light from below as millions of megatonnes of energy slammed out and up, swallowing Northern Africa, Europe and the Middle East. A spreading ring of molten rock and vaporised seawater followed it. Something flicked past the dinghy, so close Maddy flinched: a chunk of the planet had been ejected into space, breaking free of the Earth's gravity. Others pieces could be seen falling back to Earth to spread the devastation further.

The planet burned. A country-sized pall of ash and smoke already covered the seaboard of Greece and Egypt, spreading out as more rock and lava was ejected from the mantle. Continental fires could be seen as the shockwave left behind poisonous gas, flattened cities and left untold millions dead.

Geranium buried her head in Maddy's shoulder; she could feel the girl crying. She put a hand on her head, but needed the other to wipe her own tears.

I was appalling watching the death of the Earth. The destruction would be global, the pall of dark smoke existing for ages after the initial shock had passed, changing the climate for the next million years. There would be a new ice age, the destruction of the ozone layer, nitric acid rain. Another mass extinction of life on Earth.

'It's the end,' said Maddy.

A warning buzzer sounded and the AI spoke in its calm but persistent tones, 'Entry to atmosphere imminent. Advise evasive manoeuvring.'

Maddy came back to reality. The little dinghy, still on the trajectory given to it by Shiva's gravity, was following the asteroid down. Already the outside temperature was rising as the craft skimmed the upper atmosphere.

'Yes! Move to a higher orbit!'

She clutched at Geranium to steady her as their bodies were flung sideways by the AI's rapid course change. The g's rose as the ship fired its engines in a desperate attempt to achieve escape velocity without smearing its passengers into jelly.

It was several minutes before the AI reported they were in a high, stable orbit. Maddy scrambled upright, moving Geranium's hand away from where it had fallen across her face. She checked the ship's condition. Structurally it was still sound, but a great deal of its fuel supply had been expended in changing course; the AI suggested a return to the Shepherd Moon.

But the ship was no longer there.

She heard Geranium sobbing. 'Are you all right? Not hurt?'

The girl stared at her. The horror of the Earth's death gleamed like a dark jewel in her eyes. 'My family,' she whispered. 'Mother and Father. Fantasy...Wisdom...they were on Earth.'

Of course they were. Maddy reached out to touch Geranium's cheek, to soothe her, but the girl slapped her hand away.

'Do you understand?' she screamed. 'They're dead now! My family is dead!'

So were billions of other people, thought Maddy. Billions of corpses right now burning or buried under tonnes of rock, or atomised as the shockwave hit them. There would be some survivors, of course, and some refugees who might escape the planet before the blast reached them, or they suffocated from the pall of poisonous gases now streaming around the planet.

The death of the Earth.

The end, perhaps of the Elite.

She reached out again to touch Geranium, and this time the girl let her shift her dark hair from her face, to hold her hand as she sobbed and whimpered in her seat.

Their course correction had shifted the view out of the window, and it took a moment to use the attitude jets to swing the craft around so they could see the dying planet once again.

There was no sign of Shiva. It had vanished, its entire mass vaporised into heat. Where it had struck was a gaping hole in the floor of an ocean that no longer existed. Around the edge was a black ring of destruction, with splashes of discolouration spreading outwards. Much of the land around the impact zone was covered in smoke. Far away, across the Atlantic Ocean, a glimpse of the Americas could be seen as yet untouched by destruction, but bracing itself for the holocaust to come in the next few hours.

'Your parents,' said Maddy. 'Your family. They could survive. They were in New York, right?'

The girl sniffed. 'Yes. I think so. I don't know.'

'They'll have warning. They can find shelter somewhere.'

She didn't say that the shelter would have to be deep and strong to survive the withering blast of destruction even now rushing across the Atlantic toward them, to be followed by a tsunami hundreds of metres high. Nowhere was completely safe, not for a long time.

'Fuel situation is critical,' said the AI.

If the fuel ran out, they would stay in orbit until that decayed and they would plunge down into the destruction below, although they would be long dead from lack of air by then.

'Where are we?' Maddy asked the AI. 'Are there any space stations around?'

'The Masahuri D145 station is within fuel capacity. It is a weather monitoring station and satellite maintenance depot.'

'Get us to it.'

There was another course change. Maddy watched the fuel indicator creep down towards empty, but there was still enough for last minute course adjustments when the craft at last settled into a final trajectory. 'Arrival at Masahuri D145 in twenty minutes,' intoned the AI.

Maddy lay back, unable to keep her eyes open despite the ongoing annihilation below, and kept hold of Geranium's hand the rest of the way to the station.