'No,' said the Doctor wearily. 'It's just a case of two different women existing in two parallel universes. They just swapped places, that's all.'

Imperial Lee went to Lady Silk and kissed her. 'I'm so glad you could make it, babe. I thought you weren't going to see the fireworks.'

'I wouldn't have missed it for the world,' said Silk, and they both laughed.

'How long have we got?'

Imperial Lee glanced at his watch. 'Trinity is due for detonation.'

Butcher felt the bottom fall out of his world. 'How does he know that? How does he know so much about it?'

'It's all in the history books, Major,' said the Doctor. 'You see, Imperial Lee comes from the future.'

'And another dimension,' said Ace.

'Let's not confuse the Major, shall we Ace?'

'Due for detonation at five twenty-nine and forty-five seconds on Monday the sixteenth of July 1945,' said Imperial Lee.

Butcher said, 'But '

The Doctor cut in immediately. 'Don't interrupt when the madman is making his big speech,' he said.

Imperial Lee gave a hard bark of laughter. 'I'll show you who the madman is, when first this planet, then this solar system, then this galaxy, then this entire universe goes up in one vast explosion.'

'There will be time to get clear, won't there?' said Lady Silk. 'I mean, I want to watch the big fireworks start here, but then I want to get home again safe and sound and snug.'

'I thought you were kamikaze commandos,' said Ace.

'That's Lee's big thing,' said Silk. 'He says he wants to stay and go up in the big bang.'

'It will be an honour to sacrifice myself for the New Empire,' said Lee.

172.'That's right, sweetie,' said Silk. 'You do that. But personally I suspect that the apocalypse would ruin my complexion. So I'm ducking out as soon as the show starts.'

'Me too,' said Ray hastily. 'And I'm taking my records with me, man. That was the deal, wasn't it?'

Ace gave him a steady look of disgust, as though he was something unpleasant she'd found adhering to the underside of her shoe. 'Your records? Is that all you care about?'

'Don't worry, Ray,' said Silk. 'You and I will go back together. Just make sure you have the necessary equations ready to open that portal.'

'Speaking of equations,' said Imperial Lee. 'Take a look at the work he's done ready for the blast. I want to make sure he isn't going to double-cross us.'

Lady Silk went and perched on the arm of Ray's chair, taking one page at a time from the pile in the big man's lap and scrutinising each one with care.

Finally she said, 'It all looks pretty kosher to me. Not quite complete, though.'

'What the h.e.l.l are they talking about?' said Butcher.

The Doctor cleared his throat and looked at Ace. 'Would you like to explain?'

'All right,' said Ace. 'Ray here is a big science brain. His equations '

'Or incantations,' said Imperial Lee.

'Or incantations,' said Ace wearily, 'are so powerful that they will have an effect on the atomic bomb when it goes off. They'll amplify the blast. Amplify it so much that this entire universe will be destroyed.' She looked at the Doctor. 'Is that about right?'

'Not bad. You covered most of the salient points, although you rather glossed over the crucial matter of probability, the way that Ray's mathematical prediction of an event interacts with that event at a quantum level to bring it into being.'

'Anyway,' said Ace to Butcher. 'You get the gist.'

'You're all insane,' said Butcher.

The Doctor shook his head sadly. 'No, just Imperial Lee.'

Lady Silk laughed, but Lee looked angry. 'I'm getting tired of you saying that about me.' He raised his gun and aimed it at the Doctor. It looked as though he was going to use it. Butcher braced himself. If the punk started shooting he was going to try and jump him. It might be his last chance.

'What are you doing, Lee?' said Lady Silk in a calm, stern voice. 'I thought we agreed that all this bloodshed and human sacrifice nonsense was just tacky.

All we need is the equations and the desire.'

The barrel of Lee's gun wavered, and then he slowly lowered it. He looked at Silk. 'We're not short of desire,' he said. His voice was low and thick, and 173Butcher realised that he really believed in all this. Believed it and wanted it to happen. Wanted to see the world blow up like a hand grenade. 'But what about the equations?'

Lady Silk shrugged, 'Like I said, not quite complete.'

Imperial Lee looked at his watch. 'There isn't much time left.' He turned his gun on Ray. 'Get to work. Finish them.'

'All right man,' said Ray, quickly picking up his pen and a sheet of paper.

'Take it easy. I'm almost done.'

'Finish them except for the very last figure,' said Lady Silk. 'Then you can write that in at exactly the right moment.' She smiled at Lee. 'We'll time it to perfection.'

'OK, baby, OK.' Ray scribbled a few last lines of calculation, then lifted his pen and chewed at the end of it. He studied the paper, sighed, set the pen down on the arm of his chair and said, 'It's all done. I just have to write in a final term.'

Imperial Lee nodded excitedly. 'It's now five twenty-five. At five twenty-nine I will begin a countdown. We will try and coincide precisely with the detonation at Trinity, in the Jornada Del Muerto desert to the south of here.

So I will start counting at forty-five and work backwards to zero. I will say, "Forty-five, forty-four, forty-three. . . "'

'I get the picture man, I get the picture,' said Ray.

'You will put the finishing touch on your incantation, or equation,' said Lee, 'at precisely five twenty-nine and forty-five seconds, which is when they will detonate the bomb.'

Butcher glanced at the Doctor, who shot him an urgent look, as if to say to keep his mouth shut. Imperial Lee went over to Lady Silk and handed her his gun. 'Keep an eye on them. The safety's off. If they even stir, shoot.'

'With pleasure, love,' said Lady Silk. 'But where are you going?'

'Just over here.' Lee strode to the living-room windows and threw them open. Cool, rain-scented night air spilled in, chilling the sweat on Butcher's face. He watched Silk intently, but she seemed to know how to handle a gun and her hand was steady. Lee paced impatiently. He looked at his watch. 'Five twenty-six and thirty seconds.'

'Now,' said Lady Silk. 'You do have our getaway equations ready, don't you Ray?'

'Yeah, man, they're right here.' Ray patted the pile of papers in his lap.

'Because we don't want to be hanging about, do we?' Silk smiled above the gun barrel. 'What with the universe going up in a chain reaction and all.'

'Hey, that reminds me, I got to get my records ready.'

'Stay put,' said Imperial Lee tightly.

174.Lady Silk raised her eyebrows.

'Oh for heaven's sake, let him get his records.' She nodded to Ray, who scuttled from the room and scuttled back in with his yellow record bag. He threw himself back into his chair and sat clutching it tightly to him.

'Five twenty-eight,' said Imperial Lee. Then the room was silent except for the sound of the wind sighing through it. The first light of dawn was beginning to show in the dark east. The oak trees outside the window creaked and shifted in the wind, moving their branches against a sky full of retreating storm clouds.

'Five twenty-nine,' said Imperial Lee tensely. He began his countdown in a strained, cracked voice. To Butcher's eye he looked like he was on the verge of a complete breakdown. It was a pity he'd handed the gun to Lady Silk. The girl was a much cooler customer. Butcher couldn't sense any weakness in her.

'Twenty,' said Imperial Lee. 'Nineteen. Eighteen.' His voice was like two stones grinding together.

'Wait a minute, man,' said Ray suddenly.

' What? What? ' '

'Do I do it on zero or one?'

'On zero!' spat Imperial Lee. 'Zero! You do it on zero, you fool!' Lady Silk laughed. Lee frantically checked his watch.

'Four. Three. Two. One. Zero.'

Ray hunched forward and wrote briefly on the piece of paper in his lap.

Everyone stared at the window. The sky was growing imperceptibly lighter with the approach of dawn. The branches of the oak tree stirred. A restless breeze circulated into the room, bringing chill air with it.

'Well?' said Lady Silk, her eyebrows high.

'Wait,' said Imperial Lee tensely. Sweat was dripping from his brow, down his face, off his chin. 'Wait, wait, wait. It's happening.'

'If it's happening then shouldn't we get going? I mean, Ray and me?' There was a note of nascent scepticism in Lady Silk's voice.

'Wait!' said Lee.

'But maybe it's not safe to wait, darling,' said Silk. 'We were all expecting fireworks but maybe there won't be any. Maybe we won't notice anything before it's too late. So Ray and I had best go now. Better safe than sorry.

Ready, Ray?'

Ray didn't reply. Instead strangely, thought Butcher he turned to look at the Doctor, as if expecting something from him. 'There's no need to go anywhere,' said the Doctor calmly.

Lady Silk snorted. 'Come now. I for one am not hanging about to find out what the end of this universe looks like. It's already a couple of minutes after Trinity and. . . '

175.'No it's not,' said the Doctor with a shade of what Butcher thought was smugness in his tone.

Both Lady Silk and Imperial Lee were now staring at the Doctor. 'It's not what?' said Silk, virtually spitting out the words.

'It's not Trinity,' said the Doctor. 'The Trinity blast isn't scheduled until tomorrow.'

'Monday July sixteenth,' said Imperial Lee, like an automaton with a recorded message. 'Five twenty-nine and forty-five seconds.'

'Not in this universe,' said the Doctor. 'Here Trinity is scheduled for detonation on Tuesday July seventeenth at five am precisely.'

'What?' said Imperial Lee, his face glazed with sweat, his mouth hanging open.

'Details, Lee, details,' said the Doctor, smiling. 'The devil is in the details.'

'Oh, for G.o.d's sake,' said Lady Silk. 'I can't believe you've screwed this up.'

She turned to Lee, her face tight with rage. ' Can't you get anything right? Can't you get anything right? ' '

'We can always try again tomorrow,' said Imperial Lee feebly.

'I think not,' said the Doctor. He lifted his umbrella from between his knees and pointed it at Lady Silk. There was a sharp puff of compressed air and Silk suddenly went limp and dropped the gun. Ace had already leapt to her feet and, in what looked to Butcher like a carefully rehea.r.s.ed move, scooped up the weapon and pointed it at Lee.

'It's all over, Lee,' said the Doctor.

Butcher had to admit that it was neatly done. Whatever the business with the umbrella signified Butcher suspected it had shot some kind of poisoned dart Lady Silk was now standing frozen like a statue. Maybe it was curare or something, thought Butcher. A paralysing agent. The only part of Silk that moved was her eyes, desperately searching the room. Imperial Lee, however, still had the power of movement. He turned and sprinted across the room.

Not towards the door, but to the window. Ace aimed the gun at him but the Doctor shouted, 'No, Ace. Let him go.' Lee reached the window.

And jumped.

Straight down. Two stories.

Butcher and the others, except for the motionless Silk, all rushed to the windows and peered out. Imperial Lee was lying there at the foot of an oak tree, his body still, his head twisted at an impossible angle. 'He killed himself,'

said Butcher.

'That was the plan all along,' said the Doctor. He turned to Butcher, his eyes bright and intense. 'You witnessed it Major. You saw it all.'

'I'm not sure what the h.e.l.l I saw.'

The Doctor smiled crookedly. 'But now you have your missing body. The last piece of the puzzle. You can report to your superiors that the case is well 176and truly closed. The last of the spy ring has been brought to justice, thanks to you. It will only redound to your greater glory.'

'What about you?' said Butcher. 'Why don't you report to your superiors?

Why don't you take the credit?'

'Well, of course I could, being a top British intelligence operative.' The Doctor winked at Ace. 'But I'm willing to let you have all the kudos. On one condition.'

Butcher said nothing. He just stared suspiciously at the small man. The Doctor shrugged and said, 'I want you to let Lady Silk go.'