Then I lifted Tammuz over my head and threw him as hard and as far as I could in the low gravity.

He whirled through the air, arms and legs flailing, hit the side of the lunar rover and slid down it to the ground. He didn't move.

I helped Bernice up. She clutched me, then collapsed. I saw with horror that the skin of her hands and neck was reddening with far more than just bruises 'Jason,' she gasped. I winced at the pain in her voice. 'The computer! Hit s.p.a.ce bar! Arm the bombs!'

I hesitated. Bernice was dying. It was my fault. 'Jason!' Her voice was an agonized scream in my ears. Obeying her voice, I moved quickly to the computer. The program was set. Bernice was right. All I had to do was. .h.i.t a key and the program would upload to the missiles currently approaching us. The warheads would arm. And then ...

I reached out for the key. I blinked. For a moment I saw not a keyboard, but a television. Not the lunar wastes but a suburban living room.

I rested my finger on the s.p.a.ce bar.

I looked at Bernice, but I didn't see her. I saw a father hitting a son, hitting and then blaming the son for weakness. I looked at Chris, motionless in the settling dust, but I didn't see him. I saw a woman deliberately ignore her son's pleas for help. In quick succession, I saw a boy run from his own family, I saw innocence die, watched bitter violence and lies grow in its place. I saw pain and fear in the boy's face, saw him running, running from something he couldn't change and blaming himself for being unable to change it. And later, years later, I saw the guilt, the self-hatred, the wasted opportunities, the wasted life.

This wasn't new to me. I had seen it all before, on a vast canvas: the world of Cthalctose, the span of a thousand years. The ignorance, the violence, the emotional sterility, the self-denial, the wasted lives.

Except their lives hadn't been wasted. Because they had built their Ark.

The Ark that was their future. They had a future. That was something I hadn't seen much less understood, until now.

They had a future. So did I. There was hope.

Except that if I pushed the s.p.a.ce bar and armed the bombs there would be no hope for the Cthalctose. Their power supply would be used to save the Earth and they would never get a second chance at life.

By ensuring my own future, I would sacrifice theirs. I couldn't do it.

I had to do it.

I hesitated, touching the s.p.a.ce bar? Bernice was screaming at me. I had to decide? I couldn't decide. My world, their world, no world.

Bernice was dying. Earth was dying. Would it make one jot of difference what I did?

Make a decision. That's what Bernice had told me? Take responsibility for your actions.

I thought of Bernice, her smile, her tear-filled eyes as we made love, of the rollercoaster ride we had taken at Brighton, the view of Paris from the Eiffel Tower, the way it swayed as the wind caught it, the laughter in her eyes, the wind in her hair, the bad jokes, the smell of her, the feel of her holding me, touching me; slowly becoming part of me.

'Jason.' Her voice was a painful whisper. 'Don't do it for me. Do it for us. All of us.'

Her words made me think of her condition. If the bombs were armed then the Earth had a chance. We had a chance. At best we would find a cure. At worst we would die together in a flash of heat and light so intense that we wouldn't even know it had happened.

I made my mind up.

I pushed the s.p.a.ce bar.

Nothing happened, of course. Not here. Not where I could see it or touch it.

What happened, happened a thousand miles and several minutes away, in the arming mechanisms of two three-hundred-megaton nuclear warheads. I stood quite still. In the upper right-hand comer of the laptop screen a number was flicking steadily downwards.

Fifteen minutes until detonation.

I had experienced one nuclear explosion; one was one too many. I didn't want to come anywhere near another. Time to get back to the TARDIS. I moved to Bernice. She was lying on the ground? She was shaking. Her quiet moans of pain were heart-wrenching. How long did she have?

Minutes? An hour? More? Less?

I knelt beside her. I didn't even dare touch her for fear of inflicting more pain.

She whispered something. 'Sorry, love?'

'Said ... I'm sorry . . .'

'Ssshh. It's not your fault.'

'Listen ... me ... going to ... die ... you know it ... I know it . . .' She lifted her arm. I tried to take her hand. She avoided my grasp, positioning her -arm so I could see her force-field emitter. 'Make it quick for me, Jason.'

'Bernice!'

'Don't make me beg you.'

'Benny, I can't do that. What about -?'

Bernice managed a terrible chuckle. 'Don't worry. You'll only be killing one of us.'

I blinked stupidly. 'I thought -'

'So did I ... found out while you were away I was . . . wrong ... tension ... I guess. Worry. It can happen. I'm so sorry. I love you.'

'I love you too. How did you -?'

Now she was coughing, her voice cracked. 'Coming on in a s.p.a.cesuit is no fun, I can tell you.' She made a strangled noise. 'Oh G.o.d, it hurts when I ...

laugh.' She coughed. 'Actually ... hurts all the d.a.m.n time.'

My cheeks began to burn. I realized I was crying. She reached up and held me. Dying as she was, she held me. '. . . you crying for us ... or...'

'No,' I said with more anger than I realized. 'For. . .you know.'

'I'm sorry ... had to get you to ... arm the ... bombs.' Now anger swelled inside. I tried to suppress it. I couldn't. I hadn't grown up that much: The anger was a balm. It allowed me not to think about what was going to happen to us. To her.

She settled against me, gasped with pain. 'How long?'

I looked at the computer. 'A few minutes. Long enough to get you back to the TARDIS.'

'No. If you can't help me ... you leave me. You go. Now, Jason. Please.

Just do as I say this once. For me. Please. Please, Jason. Go.'

'I can't leave you.' 'You must.'

'I can't!'

'Then you ... know the other choice.'

I put my hand over hers, felt the force fields part to allow us to touch. 'I know.' I put my hand on hers. The sting of acid made me cry out. She moved her arm until my hand was resting on the force-field emitter.

'Please.'

'I love you.' 'It hurts.' 'I know.' 'Please.'

I remembered-something then, something I once heard but never understood. We never realize what we have until it's gone.

What a lesson to learn. What a way to learn it, a quarter of a million miles from the world of my birth, holding the woman I loved and trying to prepare myself to end her life.

Tears coursing down my face, I groped for the control which would shut down the force field and allow Bernice to die quickly by suffocation, instead of by suffering the lingering death I had inflicted upon her.

As I touched the control, a hand gripped my arm. Chris. I looked up, saw the big lunk through a rippling veil of tears. 'You don't understand. I have to.

I have to. It's what she. It's what. It's - 'No.' Chris's voice was suddenly very firm. He pulled my hand away from Bernice. 'Roz told me. In the helicopter. Roz told me.'

'Told you what, for G.o.d's sake!'

Chris smiled. It was the smile of an Angel. 'AG,' he said. 'CT. CT. AG. AT.

ACG. TTCT. TCAGC. CT. CT. There's more. I've got a good memory.'

I gaped. 'What the h.e.l.l are you = Bernice tugged my arm. 'Base pairs. Codon sets. Alien codon sets. It's a gene map for a virus. It's the cure, Jason. Chris knows the cure!'

I gaped.

In the helicopter. Roz told me. Imorkal.

Humans and Earth Reptiles won't be able to work together for centuries.

Chris was from the twenty-ninth century.

I had just been the backup. The one that failed. Imorkal had telepathically planted the gene sequence for Liz's antivirus in Chris's mind!

I glanced at the laptop as Chris scooped Bernice into his arms. 'Sorry, Benny. Might hurt a bit. Not for long though?' I thought I heard her whisper, 'You big lunk,' as we turned towards the tunnel entrance to the Ark, a quarter of a mile away.

I was too busy looking at the computer screen. The clock read 00:00:30.

'Chris? We have to get her to the LRV Now!' But the rover was gone.

Tammuz had taken it? We had run out of time.

'Burt the Turtle says, "Duck and cover,"' Bernice whispered. She collapsed.

00:00:00.

The sky turned white.

I expected to die. Of course I did. I was blind for some time, though the force field saved my sight as well as my life. The most horrible part was not being able to move? It brought back memories of my incarceration on Cthalctose. I'm afraid I did panic, rather? Still, being trapped in a plain of radioactive gla.s.s will have that effect, I suppose.

We were all there, Chris, Bernice and myself. Flies in amber. After my sight came back I could see perfectly well. We were only inches below the surface. It was enough to keep us motionless, paralysed. About half a mile away I could make out a dark, irregular shape in the gla.s.s. The LRV I couldn't see Tammuz, but I knew he was in that half melted tin can. I could hear him. He was talking to himself. At times he would shout, at others scream, at still others, his voice would subside to a childlike muttering and he would pray.

A long time after my sight came back I felt the ground shudder. The gla.s.s cracked around us. Aftershocks? I thought not. I thought it was probably something far more horrible.

Something about the size of a grain of sand which weighed considerably more than the average star.

Two somethings, in fact. I was right.

The singularities were free.

Shortly after I came to this realization, Tammuz began to scream. The screams didn't last long. They didn't so much stop as drop sharply in pitch, as if Tammuz was being sucked away through a long tunnel at a speed no human body could withstand.

I wondered what it felt like to be crushed out of existence by a singularity, to be ripped apart by tidal forces and smeared out around an event horizon no bigger than the end of a biro.

I lay there and waited to die.

Above me I saw the Earth erupt with flashes of silver, like. cleansing fire in the sickly yellow pus that was its atmosphere.

After a while Bernice woke up and started to moan.

I listened to her cries of pain and waited for the Doctor to come rescue us.

At times I felt like crying myself, but I was all out of tears.

Epilogue.I suppose it's fairly obvious what happened next.

The combination of Liz's codon sets and the Doctor's genetic material resulted in an almost perfect antivirus. The pity of it was that there was simply no time to fast breed enough to bombard the infected areas before the growth of Agent Yellow became unstoppable. I suppose we were lucky that the Doctor's own antivirus had stabilized the damage to the TARDIS just enough to allow him to control the singularities in their orbits through the Earth.

For my own part I think of that time, imprisoned in the 'bomb crater surrounding the Ark and I wonder if I would have got through it had Jason not been there with me. Not that I was there very long. But when you're turning into a puddle of hydrochloric acid, while watching a tenth of all life on your home planet be wiped out by X-ray bursts from pinhead singularities, life can seem terribly unfair.

n.o.body else who was with us on the Moon died. The Doctor inoculated them properly and took them back to Earth, scattering them throughout the population to act as vectors for Agent Scarlet. Even the livestock.

When he told me that I smiled. 'You're telling me a sheep saved the Earth?'

His smile was wistful. 'It was a vector, like the rest, a way to get Agent Scarlet into the food chain. Think of it like mad cow disease in reverse.'

That made me chuckle. G.o.d knows I had little enough to chuckle about. I had been scarred both physically and mentally. The physical scarring will heal with grafts and time. The mental scarring ... well I don't know about that.

After marriage it's hard to simply be alone, much less heal.

Jason and I agreed to a divorce on the same plain of radioactive gla.s.s in which we had been trapped, beneath an Earth that glimmered like a Christmas tree ornament. Each tiny rainbow sparkle signified the death of thousands. It was a curious affair, solemn, private, with few words spoken.

There were no rows, no screaming, no arguments. Jason symbolized our decision by handing me back the time ring he had stolen from me. He also decided to stay on Earth. 'I'm not my father,' he said. 'I don't run away from my responsibilities. At least not any more?'

I thought of the world he had made. That world had taken a hard knock.