'Surprised, eh?' Iris winked.

'But it's...' the Turtle stammered.'It's the same size on the inside as the outside!'

"That's dimensional transcendentalism,' Iris called, moving rather clumsily down the gangway. 'Pushed into the next stage. The interior dimensions are even slightly smaller than the exterior. Isn't that ingenious! It's the latest thing.' She flopped down on to a sofa.

The bus was a dreadful mess. There were cushions and books everywhere. To Iris, though, it looked lived in and homely and it was pleasant to have it all back to herself at last.

'I'm putting the kettle on,' said the Doctor, dodging through to the kitchen.'And then -'

'Oh, get the gin out first,' Iris called. "There's some ice in the freezer.'

'And then,' said the Doctor firmly, 'I'm getting to work on your console.'

'You'll do no such thing!' She was scandalised.

'I'm getting this ship of yours back on the road.'

'You're not touching her! I've seen how you handle yours.'

He tutted.

'What does he want to do?' asked the Turtle, sidling closer to Iris.

'We're going straight to Hyspero,' said the Doctor briskly. 'We're going to catch up with the others and those pirates. And we're going direct.'

'We can drive along the ocean floor!' Iris protested. 'It won't take long.

We're quite watertight.'

Suddenly he was determined. 'No, Iris. We're flying, I mean, through the vortex. I mean - vworp, vworp: there in a flash. That's what I mean.

We're not wasting another moment. And this time you're going to listen to me.'

'Oh, Doctor,' she smiled, as he took out the tray of ice cubes and banged them out on to the kitchen work surface. 'You've gone all masterful.'

He rolled his eyes.

Gila decided he might as well put to use the thick, muscled prehensile tail he had recently grown.'Stand back,' he told the others and lashed it at the bolted door.'I might as well make the most of this... mutation.' The lock started to break away, flaking scabs and rust with each thud and thump he gave it. The door started to give way.

Angela struggled to her feet, clutching her wound. 'Why has your mutation started to accelerate?'

He growled and shouted in triumph as their prison door burst apart. 'How should I know?' He swung round his grizzled muzzle and Sam saw with a shock just how much he had changed during these past few days.

'Come on,' he said.

They hurried out into the lower decks of the ship.

Iris fell asleep with the Turtle watching over her. The Doctor worked busily in the cab of the bus, glad that Iris wasn't awake to see him disembowel the controls like this. He found her toolbox sadly depleted and lacking, and he kept coming across things like old lipsticks and pen tops.

'You're both Gallifreyan, then?' the Turtle asked him.

The Doctor looked guarded. 'You've heard of us?'

'Everyone comes to Hyspero, Doctor,' said the Turtle. 'Even Time Lords have come here to have an adventure.'

The Doctor didn't look as if he approved. He was soldering two bits of wire that were sticking up rather annoyingly from the console, just to get them out of the way, but then they went up in a green flash. He pulled his fingers away sharply and sucked them.

'This ship is even older than mine,' he said.

Suddenly the Turtle looked alarmed. 'Doctor, I think Iris is unconscious.

That doesn't look like natural sleep to me.'

'What?' He wafted away black smoke.

'Look.'

In the dim light of the bus Iris's dishevelled body was glowing a curious orange.

'Ah,' said the Doctor.'She's put herself into a kind of restorative trance.

We haven't much time.'

'Why is she glowing orange?'

'How should I know?' he snapped.'We all do things differently. Put the lights on if it disturbs you.'

The Turtle sighed and did as he was told.'What's wrong with her?'

'She's quite vague about it. But she's picked up some dreadful bug from somewhere and she's very seriously ill. It's the whole reason for this ghastly runaround. That's why I have got to get to the Empress.

Apparently she is the only one who can cure the old thing.'

The Turtle reached out to mop the old woman's brow.'Poor Iris.'

'Aha!' cried the Doctor.'I think we're on our way.' He stuck his head out of the cab.'I've almost fixed it.'

'Are we really going to dematerialise?'

'In a few minutes."

'Is there anything I should do?'

'Your ears might pop. Have a jelly baby.' The Doctor was happy again.

He jumped into the driver's seat and started flicking switches.'And hold on to your sh.e.l.l. This might just be a little rocky.

The bus rolled unsteadily across the dark sand of the beach. He did a reckless U-turn to bring them face to face with the foaming, unfathomable sea.

The Turtle sat himself down and clutched at a handrail, just as the Doctor put his foot down sharpish and accelerated. He sped them straight at the sea.

'Here we go!' he yelled, with a grin.

And, just before the tyres could meet the cold water, the vortex opened up before them, in a swirling, foggy tube. It was a much darker and perplexing blue than the night sky and it swallowed them and the bus in one neat gulp.

Once they were gone from the beach, the vortex collapsed itself tidily, like a telescope.

TheKristeva was banking into the clouds at a few hundred feet. This was the shock that Sam and the others had to deal with when they emerged, at last, on to the deck. 'I thought I couldn't hear the sea any more!'

'We're almost there,' Gila said.

They peered over the edge and they could see the dark land ma.s.s of Hyspero several miles away. Sam glared into its glittering lights, and could just about make out the turrets and spires and onion domes.

There were cries from the crew as they continued to make merry. The escapees could hear weird, discordant music from the p.o.o.p deck. They thought they were lucky that the crew were so distracted. But then there was a noise right on their tail. Someone had discovered them.

It was the Sahmbekart who had accompanied them earlier to their cell.

He gave a guttural gasp of pleasure as they whirled in surprise.

Gila was in no mood to deal with this now. He pitched himself at the dense green bulk. The two of them fell, grappling, to the deck.

'Lifeboats!' Angela bellowed and she hobbled across the floor, wincing in pain. 'Help me,' she told Sam. Sam edged around the two reptilian men as they wrestled and grunted on the ground.

'That sounds rather nasty,' Angela muttered. 'Can you see the lifeboats?'

Sam pulled her over to the side, where a small, snub-nosed vehicle was tethered. 'Pull off the tarpaulin,' Angela snapped, and found, by touch, the electronic moorings.'We can get away in this. Leave them to it.'

Then Sam looked up and saw that Wittol, the heron creature, was with them.

'I was just coming to get you,' he said, his bill clicking and shining in the moonlight. 'It's time for some fun.'

Major Angela swore at him. He lunged at her, but both were knocked off their feet by Gila's tail, as he and the Sahmbekart crashed into them.

Sam backed off hurriedly. And then she saw that theKristeva was under attack.

'Look!' she yelled, but none of the brawlers were listening. The Bearded Lady was lashing out at whoever came closest.

Sam stared up at the sails of the ship. A great ma.s.s of flying bodies had settled about the rigging like a swarm.

All over theKristeva , cries were going up from the crew as they noticed the onslaught from above. Their sounds of celebration abruptly ceased as it became apparent that they were in some danger. Sam could hear Julia shrieking out commands.

Sam stared. The dark cloud came lower, slicing through the silk of the bellied sails. She could pick out individual shapes in the mora.s.s. They were birds. Hundreds of birds, of all types and sizes. They swooped and lunged with talons bared and their wings, she noticed, were charred black, as if these birds had swept out, en ma.s.se, from some circle of h.e.l.l and were bent on exacting revenge. There were screams from the crew as the birds flung themselves down to the body of the boat, their bills razoring and plucking at whatever flesh they could seize. The birds of the Kestheven forest, finding themselves homeless, had lost their interest in stories and the only narrative that concerned them now was one of indiscriminate revenge.

The birds were concentrating their attack on the p.o.o.p deck. This gave the escapees a few moments, perhaps. Sam hurried to finish preparing the lifeboat - abandoning subtlety and bashing at the small keyboard that worked the moorings. She unleashed a torrent of sparks and then the small boat began to unlock itself gracelessty. She clambered - heart in mouth - over the side of the ship, and into the boat. Then she glanced at the controls. Nothing she couldn't handle. She knocked the tarpaulin completely free and watched it wheel and kite far below, through the sky and into the sea. Then she yelled back at the others.

'Oi! You two! Stop enjoying yourselves and get in here!'

Wittol and the Sahmbekart crewman looked dazed. 'We're being attacked, you great lummox,' the heron snapped. He was trapped on his back, with Angela grimly pinning him down. His wings stirred as he feebly tried to free himself. 'Help Julia, Asnott. She'll need protecting.'

As the reptilian hulk lumbered quickly away, the heron prepared himself to knock back the Bearded Lady. That was when Gila spun around and, with one deft, sizzling slash, brought down his blade and hacked off the heron's head. His split neck, bleeding profusely on the deck, looked a spindly, useless thing. His head rolled off into the shadows.

'For Christ's sake, Gila,' said Sam.

'He had it coming.'

'It's all right,'Angela said.'We're all right. Come on.'

They jumped into the lifeboat behind Sam, Gila guiding the blind woman and checking that the thing was safe to fly. Then Sam started the engine, which kicked into instant, grateful life.

They left the Kristeva and her crew to fight their own battles.

Sam took a little guidance from Gila on guiding their tiny vessel, and set it streaking towards the golden lights of Hyspero. The wind whipped away their words and it was alternately hot and cold as it blew around them - full of sea mist one moment, then sandy grit, then smog and smoke fumes. Sam started coughing.

They turned to watch, when they reached a safe distance and their course was locked, as the dense ma.s.s of black birds covered the ship behind them. Someone seemed to have had the bright idea of getting rid of the attackers by setting fire to the Kristeva's sails. Up they went in a spectacular blue light. They took only seconds. They burned like paper and soon, great gouts of smoke went plunging into the sky.

"They'll sink her,' said Angela.

'Good riddance,' Gila muttered.

As they headed inland they watched the proud and bulky vessel topple slowly, backwards, out of the sky. It started, by infinitely slow degrees and then with increasing force, to slide, inexorably, hundreds of feet, back down into the sea. By the time it met the water it was all aflame, taking many of the birds with it. Their bodies whirled around and about it, like wicked mascots.

Gila grunted with satisfaction once this was all over and then he wrenched the lifeboat's controls from Sam. She protested at his brusqueness.

'Look,' he snaried,'there's no time for manners. I know this city. You don't. I know where to take us. Now get out of my way.'

They shot over the rooftops.

Night-time in Hyspero.

Below were the usual revels, carnival crowds and raucous screams. It seemed like years since Sam had last been here.

Major Angela looked bilious behind her matted beard.'I never wanted to come to this place again.'

Gila found them a s.p.a.ce to land. It was in the docks, a shady and uninviting part of town. He steered them expertly away from the crowds, to a s.p.a.ce by a jetty. With only the slightest of b.u.mps and scratches, they came rolling out of the air and landed intact in the semi-dark. The water's edge was marked with pale-green globes of light, like monstrous fruits.

'This is right next to my little place,' he told them.

'Oh,' said Angela.'Your famous secret hideout.'

'Do you want that shoulder seeing to?' he asked nastily, not liking her tone.'Or do you want both your arms snapping off?'

'You're starting to get on my nerves, Gila.'