HER DEAD SISTER was following her. Janna could hear her feet on the stone floor of the corridor. She caught glimpses of her shadow on the wall, distorted by the flickering torchlight. She heard the girl whispering the name: ‘Janna, Janna, Janna…’

Nowhere was safe. Her sister knew all the places, all the hidey-holes and the darkest shadows.

‘All right,’ she shouted into the gloom at the end of the passageway. ‘It should have been me that died. I know that. I’m sorry. I can’t change it – if I could, I would.’ She sank to her knees. ‘I’m so sorry. So sorry.’

The lights flickered impossibly as a breeze ruffled Janna’s hair. The torches looked like real flame but they were run by the same fusion generators that powered everything in the castle. They wouldn’t suffer in a breeze.

Still kneeling, Janna looked round. How could there be a breeze, here, deep under the castle? It was getting stronger, blowing her hair round her pale, grubby face. An unholy noise echoed off the stonework, growing and fading with the breeze – a rasping grating sound. The walls and floor were bathed with a blue light. Shadows in the nearest alcove deepened as the noise grew.

‘Stop it,’ Janna yelled into the fury. ‘Stop this. I’m sorry!’

And it did stop. The wind died, the light faded, the noise was gone.

In its place a large blue box stood solid and confident in the alcove. Janna backed into the shadows and watched as a door in the front of the box opened and a man stepped out.

He was tall and thin with spiky hair and eyes that were wide with interest and amusement. Eyes that fixed unerringly on Janna despite the dark shadows that enfolded her.

‘Hello,’ the man said cheerfully. ‘What’s your name, then?’ He took a step towards her, allowing the silhouette of a woman to step out of the box behind him, her face hidden behind the man’s shoulder.

But Janna didn’t wait to see the woman’s face. She turned and ran. She could hear her sister’s ghost running after her.

‘It doesn’t look like the most brilliant theme park in this part of the cosmos,’ Martha said. ‘It looks like a damp, gloomy tunnel.’ She sniffed. ‘And it smells.’

‘It’s not damp,’ the Doctor said. He plunged his hands into his coat pocket and sniffed as well. ‘Well, not really. Not damp damp. Doesn’t smell too bad, either.’ He peered into semi-darkness. ‘I’ll give you gloomy, though. Lots of gloom. Looming gloom. A real gloom loom, assuming gloom can loom.’

‘So where are we really?’

‘Really? Outside the TARDIS. In a smelly, gloomy, not-really-damp-damp tunnel, I should think. Pity that girl ran off, we could have asked her.’

‘What girl?’

‘The one that ran off. When she saw you.’

Martha’s eyes widened. ‘Excuse me, but it was you that frightened her off. I didn’t even see her.’

The Doctor wasn’t listening. He pulled the TARDIS door closed, then marched off down the gloomy passageway. ‘Maybe we’re a bit early,’ he said. ‘Maybe they just haven’t opened yet.’

He hesitated as he reached a junction, pointing first one way then the other. ‘Eeny meeny miny mo,’ he murmured. He set off along the left-hand passageway. His delighted voice echoed back to Martha. ‘Oh, it’s mo!’

‘Early as in, they’re still having breakfast?’ Martha wondered, catching him up.

‘Or early as in the place is still a frontier fort under almost constant siege from either Anthium or Zerugma, and they haven’t actually sorted out the peace treaty and built it yet.’

Martha ran to catch him up. ‘You said guided tours and coffee shops,’ she accused. ‘Not frontier fort and constant siege. You said exhibitions and historical re-enactments.’

‘Yeah,’ the Doctor conceded. ‘But so much better when you arrive in the middle of the real thing. I mean, just think about it.’

‘I am thinking about it.’

‘Real siege warfare. Real people in real situations. Real history.’

‘Real blood, real death, real destruction and real danger.’

The Doctor paused to inspect one of the torches flickering on the wall. He seemed to be rolling the idea round his mouth. ‘That too,’ he decided eventually. ‘You know, this isn’t real though. Look at it – that’s clever.’

Before Martha could stop him, he stuck his hand into the flames. ‘It’s all right,’ he said, seeing her expression. ‘Like I said. Not real. Brilliant, clever, real-istic. But not real. They must have a fusion generator somewhere. Means we can’t be far off. War’s probably been over for years.’

‘Probably?’

He was off again. ‘Well, possibly. Maybe.’ He spun round and continued walking backwards so he could look at Martha behind him. ‘I don’t know – let’s find out. We need to find someone to ask really. Like that little girl.’

Martha stopped.

The Doctor stopped too. ‘What?’ he asked, not turning to see what she was looking at.

‘Maybe,’ Martha said slowly, ‘we could ask a sinister cloaked figure who looks like he’s enrolled as Chief Frightener at the Monastery of Doom?’

The Doctor’s eyes narrowed. ‘Behind me?’ he whispered, pointing over his own shoulder without looking.

Martha nodded.

‘Sinister monk? Easy!’ He spun round again. ‘Hello brother, can you spare a… No, hang on, that’s not it. I wonder if you can help us? Yes – that’s right. Help – any chance?’

The monk was standing several metres further along the passageway. His head was slightly bowed so only darkness was visible under the hood of his black cloak. His hands were clasped in front of him, each folded into the opposite sleeve. As the Doctor spoke, the monk raised his head slightly. He lifted one hand – a pale, gnarled claw – and silently beckoned.

‘Guided tour, you see?’ The Doctor was off after the monk. ‘Come on, Martha. Told you – historical re-enactment.’

‘Yeah, but re-enacting what – the Black Death?’

‘Could be. What did you expect?’ the Doctor said as they followed the cloaked figure. ‘The Spanish Inquisition?’

The monk led the Doctor and Martha up a flight of twisting stone stairs into a wider, better-lit corridor. There were paintings on the walls and the slight smell of damp and decay faded.

They passed several other people – another monk, a soldier in armour that was clearly plastic, as if part of a child’s dressing-up set, and a crocodile man. For a moment, when he first stepped out of a doorway, Martha thought he really was a crocodile man – scaly skin covered by strips of dark leather; clawed, reptilian feet and hands to match; a jutting snout that was full of teeth. Small dark eyes gleamed in the flickering light. Nostrils at the end of the snout seemed about to flare.

But then, they didn’t. They sort of squashed inwards. And now Martha could see that the teeth were obviously painted on the mask. The claws on the feet bent like rubber as they caught on the paved floor. The reptilian skin was drawn onto the costume, not even moulded. Up close, it all looked a bit cheap. The gleaming eyes were staring through holes cut out of the mask.

The crocodile man raised his hand in greeting, and nodded. The mask shifted and looked in danger of falling off. Martha heard a sigh of irritation from inside. She smiled and waved back.

‘What is this – fancy dress weekend?’ Martha hissed at the Doctor.

‘That was a Zerugian,’ the Doctor said, apparently impressed.

‘It was a costume. It was a man dressed up.’

‘In full ceremonial battle armour.’

‘In a cheap mask.’

They had stopped, and the monk was beckoning impatiently again. Martha frowned as she watched the withered hand with its talon finger curling. She reached out and grabbed the hand. It was squishy and the long nail on the end was bendy like the crocodile man’s claws. It came off – a glove. Embarrassed now, Martha held it out for the monk to take back.

Under the hood, in the better light, Martha could see a young man – a very ordinary young man – staring back at her in surprise.

‘Who are you? Where are we going?’ Martha demanded.

The man shook his head slightly and put his finger to his lips as he pulled his glove back on.

‘Silent order,’ the Doctor said.

‘He isn’t even a real monk,’ Martha said as they continued on their way.

‘I didn’t mean he belongs to a silent order of monks. I meant, he’s been ordered to be silent.’

‘But – why?’

‘Been to Disneyland?’ the Doctor asked.

‘What’s Disneyland got to do with it?’

‘Does Mickey Mouse speak?’

‘Sort of squeaks.’

The Doctor didn’t reply, but followed the ‘monk’ through a doorway into a huge and impressive room. ‘Now this is more like it. Thanks, Friar Tuck,’ he said to the monk. ‘Mickey Monk – what a nasty thought,’ he murmured as the monk bowed and left. ‘And you’d never get a hood to fit over the ears.’

Martha hardly noticed. She was looking round the room. It was enormous, like the banqueting hall of a huge medieval castle. A long table ran down the middle of the room, with other smaller tables off to each side. All were covered with the same faded, thinning velvet material. There were several figures in alcoves – knights in advanced armour like the costume she’d seen earlier, but more robust and made of heavy, dull metal – the real thing.

Paintings, darkened with age, hung on the walls. The far end of the great room was dominated by an ornate mirror that reached up from just above the floor to well above Martha’s head. Two large futuristic guns, like rifles with battery packs added, were fixed in a cross over a round shield.

‘Parallax rifles,’ the Doctor said, seeing where Martha was looking. ‘Nasty. They wobble your insides into a different place from your outsides. Then back again, which at least stops it getting messy. But the trauma’s enough to kill even a Zerugian.’

‘And where are we, exactly?’

‘In Extremis. Which is where we’re supposed to be. Judging by the pictures at least.’ The Doctor was walking slowly round the room examining the paintings. ‘Various battles between the Anthiums and Zerugians. Think I got the timing slightly wrong, but this is definitely Castle Extremis.’

‘Greatest theme park in the cosmos?’

‘Yeah. Well, it will be. One day. Looks like we’ve arrived before it really got going. In the years before the peace treaty it was all a bit cheap and cheerful. Well, cheap and dreadful, actually. Fusion generators, advanced battle fleets, and cheap plastic dressing-up costumes.’

There was a man standing in the doorway. Martha could see him reflected in the mirror, and she turned abruptly. The man was of slight build and wearing a plain, dark suit like Martha might expect to find in a department store. His dark hair was greying slightly at the temples and thinning slightly on top. But his craggy, lined face revealed he was older than his hair suggested.

‘Can I help you?’ the man asked in a rich, deep voice.

‘Oh I do hope so,’ the Doctor said. ‘I’m sorry to turn up unannounced.’

‘You are here for the…’ the man’s voice trailed off.

‘The thing, yes. Don’t tell me we’re not on the list. Got my invite – complete with “plus one” on it and everything.’ The Doctor was brandishing his wallet with the psychic paper.

‘How come no one else will talk to us?’ Martha asked as the man examined the paper – which would show him something relevant that he expected to see.

‘Oh, a stupid rule. I suggested they do away with it for the duration of these sessions. I suggested they do away with the guides completely, come to that. But, well – tradition. That poor lad Gonfer had to write me a note saying you were here. The guides are not permitted to speak while in costume and on duty.’

‘Mickey Mouse,’ the Doctor said.

‘The Doctor and Miss Mouse,’ the man replied, nodding with interest. ‘Welcome to Castle Extremis. It is an honour to have observers from the Galactic Alliance attend the Treaty Talks.’

‘It’s Martha, actually,’ Martha explained. ‘Just ignore him.’

‘My apologies, Miss Martha Mouse.’

Martha glared at the Doctor.

‘But it is so unusual for GA observers to declare themselves,’ the man went on. ‘I knew, of course, that two observers were in attendance, monitoring the proceedings. But in the normal run of things they remain anonymous, sending their reports surreptitiously and only intervening to use their very special powers of jurisdiction and release of weapons in extreme emergencies.’

‘Well,’ the Doctor said, ‘unusual circumstances and all that. And you are?’

The man actually took a step backwards in surprise. His voice rose an octave either in shock or anger: ‘I am High Minister Defron. I am the man who brought the two sides to the negotiating table in the first place and brokered the peace.’

The Doctor grinned and clapped High Minister Defron on the shoulder. ‘Course you are,’ he said. ‘We knew that. Didn’t we know that, Martha Mouse?’

‘Yeah, like we know each other’s names,’ Martha said. ‘Isn’t that right, Doctor Donald Duck?’

‘So,’ the Doctor said as Defron led them along yet another corridor, ‘why don’t you fill us in on the way?’

The High Minister had told them he was taking them back to the negotiating chamber where they could meet the delegates from Anthium and Zerugma. ‘Fill you in?’ he asked, confused.

‘The treaty conference,’ Martha prompted. ‘How did you manage it?’

‘It’s a big deal,’ the Doctor said. ‘Must have taken some doing. We’d like to know how you see the situation. From your perspective.’

‘The press is not invited until we’re ready for the final signing ceremony,’ Defron said. ‘This isn’t a time for self-congratulation or for soundbites.’

‘Course not.’

‘Though I confess I feel the hand of history on my shoulder. What do you need to know?’

The Doctor’s eyes widened, and he shot Martha a ‘get him’ look.

‘The Doctor’s the expert,’ Martha said. ‘Maybe you can give me the background. I’m kind of new to the team.’

‘But a tremendous asset,’ the Doctor assured her. ‘Duck and Mouse – what a partnership. So whose idea was it to have the signing ceremony here at Castle Extremis?’

‘It seemed the obvious place,’ Defron said. ‘There may have been peace for twenty years, but Anthium and Zerugma are still technically at war.’

‘Until the treaty is signed, right?’ Martha said.

‘If it is signed,’ the Doctor said quietly.

‘Oh it will be signed,’ Defron assured them. ‘We are down to the fine details now.’

They passed an open door. Through it Martha could see a room in the middle of being decorated. More than that; it was being renovated, she realised. An ornate fireplace was in pieces on the floor, and several of the firebrand wall lights had been pulled away, trailing wires.

‘Be good when it’s finished,’ she said.

Defron shook his head. ‘I despair of those two maintenance robots sometimes,’ he said heavily. ‘Just so long as the state rooms are ready in time. The rest can wait. They’ve managed with it in this condition for long enough, as a tourist attraction. Not that it was terribly popular, that’s why they needed all those Lottery grants. Even so – who wants run-down facilities and gimmicky guides? The Galactic Alliance plan to turn the place into some sort of historical theme park after the treaty. A place the peoples of the cosmos can visit, where they can sigh at the mistakes of Anthium and Zerugma, and learn from their reconciliation.’ He shook his head sadly.

‘It’ll never catch on,’ the Doctor agreed. ‘The Galactic Alliance is a neutral body, bit like the United Nations,’ he went on quietly to Martha. ‘They have control of the castle now.’

‘Why?’ she whispered back.

‘Because whoever controls Castle Extremis controls the whole region. It’s right slap-bang in the middle of the only safe route through this area. So give it to a neutral power and occupy it with a peacekeeping force and – fingers crossed…’

‘Peace treaty?’

He nodded. ‘The castle is at the head of the Sarandon Passage. Anthium one side of the divide, Zerugma the other. If either side wants to rule over its neighbour, it has to control Castle Extremis. The treaty is to formalise the peace, and officially hand over Extremis to the GA.’

‘So they can make it into a theme park?’

‘That’s right. What a plan, eh? Just think of what could have happened if North and South Korea had decided to ditch their weapons programmes and buy Alton Towers instead. The soldiers of the Ninth Legion could have slept safely on their bunks if only Hadrian had opened his wall to tourists and charged a modest fee to walk along it and sketch pictures.’

‘You reckon?’

The Doctor sucked air through his teeth and considered. ‘Well, maybe. History is all about maybes.’

There were sentries outside the double doors at the end of the passage. Their armour looked more streamlined and modern than the costume – or the real thing – that Martha had seen. It was like a cross between modern combat gear and the sort of padding worn for American Football. The two men snapped to attention as Defron approached. He ignored them and strode into the room.

‘I am pleased to announce that the GA Observation Team has arrived,’ he said, and gestured for the Doctor and Martha to enter.

‘Hi,’ the Doctor said amiably.

Martha raised a hand in greeting. She didn’t say anything, because she was too busy looking at the people sitting round the horseshoe-shaped conference table that dominated the room.

Defron made his way to a seat at the midpoint of the crescent. There were two spare seats at one end, and Martha followed the Doctor as he headed for one of them.

‘So,’ the Doctor said. ‘I’m the Doctor and this is Martha. Why don’t you take a quick moment to introduce yourselves, and then you can just carry on as if we’re not here. How’s that sound?’

Apart from Defron, there were four other people sitting at the table. An elderly lady with snow-white hair, a middle-aged man with broad shoulders and flint-hard eyes, and two crocodiles. A crocodile turned to look at Martha. One reptilian eye glittered, while the other was covered by a black patch. The ends of a livid white scar emerged from above and below the eyepatch. The creature’s scales glistened as it turned, catching the light, and a string of pale saliva dripped from its jaws as sharp white teeth snapped together.