At that moment a hidden door in the wall opened with a rusty screech, revealing a dilapidated banqueting hall. The Doctor and Donna entered. Again, the place was a ruin - a pale reflection of its former glory. But Donna could hardly believe what she saw next. Standing about, looking annoyed, were some of history's most famous leaders, artists and scientists. Was that Cleopatra? Winston Churchill? Michelangelo? Galileo? She stared open-mouthed. They were arguing between themselves and demanding to be released immediately.
'Hello. I'm the Doctor.'
Everyone fell silent and stared at the newcomer. Then, with a whirring noise, Momus hovered into the room. The crowd looked up and gasped at the computer suspended in midair.
'And this is your host, believe it or not.'
The room dissolved into anxious chatter once again.
'I've always dreaded fancy dress parties dreadfully,' said Noel Coward, rolling his Rs. 'And now I know why, dear boy. I mean, who is that supposed to be?' He pointed at a man in a ruff.
'I could speak the same of ye, sir!' protested the man.
'That's Sir Francis Drake,' whispered the Doctor.
'Huh - if he's Francis Drake, I'm Lillie Lantry!'
The Doctor looked around him at all the famous faces. He smiled proudly. 'It's like an historian's idea of heaven. What am I saying? It's my idea of heaven!'
'Oh - my - goodness!' cried Donna. 'It's Cher!'
'You're darn right it is,' said the singer. 'And I'm due in the studio in twenty minutes. Can someone tell me what the heck I'm doing here?'
'If only you could turn back time, eh?' smirked Donna. 'Turn back time. Geddit? Oh, please yourselves.'
'And there's Cleopatra,' beamed the Doctor. 'She's Greek, you know, not Egyptian. Common mistake.' He noticed someone else. 'Charlemagne! Hello! Just tasted your dinner. Don't have the soup.'
'Can you explain what is going on?' demanded the Emperor. 'I have a very important meeting with the Pope.'
'I know,' replied the Doctor. 'But it's probably best if I don't explain. Just put it down to too much cheese last night - y'know, weird dreams - and I'll have you back at court in a trice.' He paused. 'Hopefully.' The Doctor spotted another guest. 'Oh, look, it's Caligula. Not as bad as they make out in I, Claudius. And Joan of Arc. Woo! Good old Joan. What a woman. And there's Winston Churchill... and Beethoven - loved your Fifth - and Boudica... or is it Boadicea?
'Neither, actually,' she replied, with a disgruntled snort. 'It's Bo - '
'You approve of my guests then, Doctor?' said Momus, cutting her off.
'I approve of them, but they shouldn't be here. You're messing with the flow of Time. Do you know what this could do to Earth's history?'
'Nowhere in the Universe has produced so many great minds,' said Momus, his lights flashing and his wires twitching. 'So many great leaders, writers, musicians, explorers...'
'What is going on?!' protested Michelangelo. 'I've got a model waiting in the studio!'
'Huh, that's nothing,' said Cleopatra. 'I've got Mark Anthony in mine!'
'Must be some trick of the Devil's making,' offered Joan of Arc.
'The Devil has more of a sense of humour, my dear,' replied Noel. 'But you're right - it is diabolical. Just look at the decor.'
While everyone was busy shouting and moaning, the Doctor and Donna slipped away from the crowd and headed for a quiet corner.
'Oi, Momus!' called the Doctor, and he beckoned the computer over. 'I think it's time for some explanations. Your guests don't seem too thrilled to be here.'
'I was once a great computer, built by the Ridion Alliance's finest scientists,' said Momus, sadly. 'But after the Seven Hundred Year War, my planet's population descended into a terrible dark age. All their great buildings fell into ruin, their sophisticated ideas were forgotten, their cultural achievements lost. After a generation or two, they no longer understood what I was for. I was left, all alone, in this palace. With nothing but my thoughts for company.'
'So you fancied making a few new friends?' frowned Donna.
'I brought these people here for more than selfish reasons,' he replied. 'I wanted to stay faithful to my people - that is how I was programmed - and help them progress into a new age of enlightenment. These great Earth minds will assist me in my task.'
'Meddling in Time and kidnapping people contravenes Galactic Law,' said the Doctor.
'I was only borrowing them.'
'Yeah, officer, I was only borrowing that five million they left hanging around in the bank safe,' added Donna, sarcastically.
'Civilisations rise and civilisations fall,' said the Doctor. 'It can't always be scientific discoveries and building huge cathedrals. You need the scratching about in the mud bit, too.'
'But for how long?' asked the computer. 'I have already been waiting for what seems like an eternity.'
'But these people are needed on Earth. It's not right to take them away. Look at Charlemagne. He's in the process of changing the face of Europe. Winston Churchill. The world could end up under Hitler's control without him. And as for Cher... well... we wouldn't have, er... Dead Ringer For Love.'
'Meatloaf could have done it with someone else,' said Donna.
'Fair enough,' replied the Doctor. 'But you get my point.' He stared up at Momus. 'Why should Earth suffer so you can try and enlighten this planet? That goes against everything you stand for, surely?'
Some of Momus's lights dimmed and his wires drooped. 'It is a rational argument,' he said, sadly. 'But what will become of me?'
'Your planet left you,' said the Doctor. 'You don't owe them anything. They've got to build their own civilisation now - in their own time.' The Doctor paused for a moment. He looked suddenly sad. 'I understand what you're going through, Momus. I know what it's like to be alone - to be the last - but you've got to take care of number one now. You can teleport yourself anywhere you want. Make the most of it. There's nothing for you here anymore.'
'You are right, Doctor,' said Momus. 'It is not easy to leave behind the things you know... and once loved.'
'Tell me about it,' said the Doctor.
'But my time here is over. Maybe one day I will return.'
'So... would you mind getting this lot back home?' asked the Doctor, pointing at the crowd.
Momus's lights flashed, he emitted a strange buzzing noise, and with a blindingly bright flash of green light all the guests in the room disappeared.
'They are back where they belong now, Doctor,' said Momus.
'By the way, how did you do that?'
'I have mastered the K.R.H. Timeloop theory.'
'Very clever. Very clever indeed.'
'The what?' asked Donna, in a whisper.
'No idea,' the Doctor whispered back.
'Now you too must go.'
'Yeah, just drop us off in the Ardennes,' smiled the Doctor. 'But promise me, as soon as we're gone, you'll get away from this planet. There are billions of worlds out there waiting for you. Travel! It broadens the mind.'
'It really does,' said Donna. 'I can vouch for that.'
'Thank you, Doctor,' said Momus. 'I promise you.'
And before the Doctor could say another word, he and Donna found themselves back on the path in the forest.
'I know how he feels,' said Donna, as they headed back to the palace. 'Stuck with a bunch of primitives. It was like that time I worked in telesales. I have never met such a load of losers. I couldn't take more than two days. There was this one bloke and he did not stop going on about Manchester United. I was bored out of my mind...'
'So, where are we going next?' asked the Doctor, quickly changing the subject.
'1985, of course,' replied Donna. 'Remember? Shopping trip? Puffball skirt? I love shopping!'
'Oh, yes...' The Doctor attempted to smile. 'Shopping. Great.' He paused. 'Is it all right if I wait in the TARDIS?'