The only answer was the hiss of static.

'Life support's out,' reported Thelesa, her questioning tone betraying her shock and grief. 'He's... gone.'

Locklear turned away from the communication desk. The flight deck of the G.o.dspeed was in near-darkness, the faces of the crew lit by flashing viewscreens.

'What's our power situation?' she asked Keinholz.

Keinholz tugged at the collar on his uniform, as he always did when it was bad news, and indicated the schematic diagram on his viewscreen. 'Down to thirty-five per cent. Never seen anything like it.'

'Still no idea of the cause?'

'Something in section twelve. That's the centre of the energy drain, where it started.'

'Whatever it was that Tobbs found,' said Thelesa, brushing away something in the corner of her eye. 'He said there were "barnacles".'

'You heard of anything like that, Professor?' said Locklear, turning to the ship's xen.o.biologist.

Ferrier frowned. 'No, Captain, but I suppose a s.p.a.ce-borne creature is theoretically possible. Several extremophiles have been known to survive in a vacuum.'

Any excuse for a biology lecture, thought Locklear.

'Power reserves down to thirty per cent,' said Keinholz with all the gravity of a tolling bell.

Locklear turned back to Thelesa. 'Looks like we have no choice,' she said, trying to sound confident despite her stomach tightening with dread. 'Send out a distress call.'

Thelesa nodded, swallowed, and pressed the activation sequence. The mayday signal sounded, a succession of urgent bleeps. Then it faded away to silence.

'What is it?' said Locklear. 'What's happening?'

Thelesa's fingers ran over the controls of her workstation, to no effect. She shook her head. 'The power-drain, it's affecting the comms.'

'Of course,' said Keinholz resignedly. 'The transceiver is based in section ten.'

'We might've got a message out for a few seconds, but that's it,' said Thelesa, her voice filled with fear. 'There's not enough power left to broadcast a distress signal.'

Locklear stared at the main viewscreen, blacked out due to the power shortage. Every instinct made her want to scream, but she had to do her duty, she had to remain calm. 'So we're stuck in a dying ship, with no means of calling for help, and n.o.body to come to our rescue.'

'What you talking about?' said a brazen male voice. 'I'm here, aren't I?'

Locklear turned to see a tall man standing in the middle of the flight deck with his arms folded and his chin raised.

'Who are you?' said Locklear indignantly. 'What are you doing here?'

It was difficult to see in the gloom, but Locklear thought she could see his lips curl into a mocking smirk. 'I got your message,' he said matter-of-factly. 'I'm the guy who's gonna save your lives. But that's a bit of a mouthful, so you can call me "the Doctor".'

Locklear stared at him. The rest of the crew were also staring at him. The man relished being the centre of attention, acknowledging each of them with a cheery nod. 'The Doctor?' said Locklear, looking him up and down. He appeared to be wearing a jacket made of tanned animal hide.

'That's right, don't wear it out,' he said, as he jogged across to the engineering workstation. The electric blue glow from the schematic diagram illuminated an aquiline nose, two protruding ears and a gaze of ruthless determination. 'Here's the deal. Do exactly as you're told and you might just get to live.'

'Are you threatening us?' said Locklear.

'It's not me you have to worry about.' While Keinholz stared at him in disbelief, the Doctor tapped at the workstation keypad. 'Reserves down to fifteen per cent. It's gonna start getting very dark, very cold and very hard to breathe. No, what you need to worry about are these little tykes.' The Doctor held up a pen-shaped device which buzzed and glowed blue. The main viewscreen flashed into life.

Locklear gasped. The viewscreen showed the ship's starboard hull, facing aft. The ship's surface was coated in barnacles. As she watched, more of the creatures drifted out of the blackness and adhered themselves to the hull.

'What the h.e.l.l are they?' she said.

The Doctor shrugged. 'No idea. Never seen them before. Just picked them up on my scan when I came in.' He grinned wildly. 'A brand new form of life. Fan-tastic!'

'And they're the source of the power outage?' said Keinholz.

'Evidently,' said Ferrier, gazing at the viewscreen in awe. 'If they can eat through metal, they could've chewed through the power lines.'

'Do they look like they have teeth?' said the Doctor incredulously. 'Do you see any teeth? I don't see any teeth.'

'Whatever they are, they're attacking my ship,' Locklear snapped at him. 'If we don't deal with them, we're dead. Keinholz, use the plasma cannons.'

Keinholz began tapping at his keyboard. The Doctor turned on Locklear. 'So, what? You discover a new life form, and what do you do? Shoot at it!'

'We have to defend ourselves, Doctor,' said Locklear. 'Don't you think you should try to understand them first?'

'What is there to understand? They're not intelligent. We can hardly negotiate. Once we're finished, Professor Ferrier can dissect their remains.'

'Plasma cannons energised, Captain,' said Keinholz.

'Then destroy them,' said Locklear firmly. 'Maximum dispersal. Wipe them out!'

'Listen to me-' began the Doctor, but the howl of the cannons drowned him out. The floor shuddered as the sound was conducted through the fabric of the ship.

On the viewscreen, a shaft of plasma flashed through the darkness and one of the creatures exploded into a cloud of dust. The cannon fired again, winging another of the barnacles, causing it to spin away into the void. It fired again, and again, but each time it fired, more of the creatures appeared. They swarmed over the side of the hull, streaming towards the viewscreen like a slow-motion snowstorm.

'Keep firing!' said Locklear, and muttered, 'Where are they all coming from?'

'They can't be reproducing,' said Ferrier doubtfully. 'Can they?'

'Plasma cannons losing power,' said Keinholz. 'We can't keep this up much longer.'

'Keep firing,' repeated Locklear, even as the creatures inundated the viewscreen.

'Oh, you stupid, stupid apes,' said the Doctor. 'Work it out. Energy's their meat and drink. So firing plasma at them, you're just inviting more of them to lunch.'

'That would explain the power drain,' said Ferrier.

'And the life-support failure Tobbs experienced,' said Thelesa sadly.

'They're breeding,' said the Doctor. 'Converting your ship's energy to ma.s.s.'

'Captain, we're running out of power,' said Keinholz.

Locklear sighed. 'All right. Stop firing. Stop firing!'

Keinholz tapped a b.u.t.ton and the cannons stopped.

Locklear leaned towards the Doctor, her face inches from his. 'So, Doctor. What d'you suggest?'

'Answer's obvious,' said the Doctor. 'But first, you tell me something. What are you doing out here? What's the purpose of your mission?'

None of the crew responded, so Locklear answered. 'Our mission is to seek out unregistered planets and stake claims on behalf of the parent company.'

'What sort of claims? Research? Colonisation? Mineral extraction?'

'What the company does with them is none of our business.'

'No, your job is to roam the galaxy calling dibs,' said the Doctor. 'You humans like to think you own things you had nothing to do with creating. OK. Listen. I get you out of this, you leave this system, never to return. And you tell your company there was nothing of interest here, so these barnacles can get on with their lives in peace. Agreed?'

'Very well,' said Locklear. 'There was nothing of value here anyway.'

'Doctor,' said Keinholz. 'We're down to two per cent. What is the solution?'

'Simple. Switch everything off. Put the ship on silent running. They're attracted by energy, so make them think there's no more left. Lunchtime's over.'

The crew didn't respond. Locklear nodded wearily. 'Do it.'

Keinholz pressed a sequence of switches and one by one, the workstations around the flight deck went dark. The ever-present background hum of the ventilation system faded away and silence filled the room.

'All systems off-line,' said Keinholz. 'Including life support.'

'What?' cried Thelesa. 'But without that, we'll suffocate.'

'No you won't,' said the Doctor. 'You'll freeze to death first.'

'He's right,' said Keinholz. 'Temperature dropping below ice-point.' As he spoke, his breath clouded in the air.

'Good, good.' The Doctor checked the readouts at Keinholz's workstation. 'We have to convince them this ship is just a derelict lump of junk, floating in s.p.a.ce.'

'And then what?' said Ferrier frostily, rubbing her arms for warmth. 'They'll just become dormant, stuck to the hull. We won't be able to turn the engines back on.; 'You will,' said the Doctor. 'Someone just has to make them a better offer.' He strolled over to the rear doors, buzzed his pen-shaped device, and they slid open.

'Where are you going?' asked Locklear.

The Doctor paused in the doorway. 'The TARDIS. My wheels. You can come along if you like.'

Locklear stood in the TARDIS control room, gazing open-mouthed at the high, curved walls pulsing with green light. She'd never seen anything like it before in her life.

The Doctor darted around the central console, flicking switches embedded in its coral-encrusted surface. As he did, jets of steam hissed out of vents in the floor. He grinned the most manic of grins. 'Nearly there!'

There was a stomach-churning rumble and the central gla.s.s pillar of the console began to rise and fall. Then the rumbling stopped with a crunch. The Doctor slammed down a lever and sprinted over to the exterior doors. He pulled them open in a grand gesture to reveal the G.o.dspeed floating through s.p.a.ce a short distance away.

Locklear approached the doorway warily. 'I'm guessing there's some sort of force field preventing us being sucked out?'

'You guess correct. I can see why they made you captain.'

Locklear nodded dumbly and peered outside. She could just about make out the barnacles covering the G.o.dspeed's hull. 'So how do we lure them away?'

The Doctor dashed back to the console. 'Power, Captain Locklear. Power!'

A few moments later, out in the darkness of s.p.a.ce, the lamp on the top of the TARDIS started to flash. It sent out a dazzling, swirling beam of light, like a lighthouse, on and off, picking out the barnacles on the hull of the G.o.dspeed.

Very gradually, a couple of the barnacles detached themselves from the hull and began to swim through the vacuum towards the TARDIS. Then a few more barnacles detached themselves and followed. Then the entire encrusted body crumbled away as the whole ma.s.s of barnacles released the ship and swarmed slowly towards the police box.

The Doctor stood in the doorway, waving the creatures towards him. 'That's it! Come to Daddy!' Then he smiled and slammed the doors shut.

The first of the barnacles settled upon the wooden panelling of the TARDIS and its slanting roof. Then more arrived, clinging to the sides, the roof and the underside, burying it in a tightly cl.u.s.tered ma.s.s of sh.e.l.ls. Then more barnacles covered those barnacles, until not a glimpse of the police box remained.

In the TARDIS, a warning alarm hooted and the engines made a low grinding sound. The Doctor checked the monitor, which showed a series of revolving circles. 'Yes, I think I've got them all. They're tucking in, happy as Larry.'

'But won't that mean you'll be stuck here?' said Locklear. 'They'll be drawing power from this... ship?'

'Oh, the TARDIS has plenty of welly, don't worry about that,' said the Doctor proudly. An instant later, the lights went out.

'You were saying?' said Locklear.

The Doctor dashed around the console, adjusting switches by the light of the glowing central column. 'OK, we're gonna have to be quick, they're breeding like, well, like barnacles.' The controls didn't respond, so the Doctor pulled a hammer out from under the console and whacked it. Part of the panel exploded into sparks, but the central column started moving up and down.

The Doctor laughed. 'First we dematerialise, taking our new friends with us, then rematerialise in the inner asteroid belt, nice sunny spot, and dematerialise leaving them behind to feed!'

Out in s.p.a.ce, the barnacles clinging to the TARDIS had multiplied until it was buried beneath a sphere of thousands of b.u.mpy sh.e.l.ls. The creatures ejected clouds of spores which swiftly grew into minuscule barnacles, which attached themselves to the sphere and quickly expanded to become full-size barnacles.

Then there was a wheezing, groaning sound, and the ball of blistering barnacles faded away.

In the flight deck of the G.o.dspeed, the emergency lights grew brighter. Then the main viewscreen lit up, showing the hull of the ship now clean of barnacles, followed by all the workstation viewscreens.

The crew stared at each other in surprise. Keinholz checked his controls. 'Emergency generators on line. Power supply at forty per cent and rising. We're saved. We're saved!'

Thelesa, Ferrier and the rest of the flight crew cheered in relief. The ventilation hummed on and blasted the room with warm air. Then the overhead lights flickered into life and the deck was restored to its normal bright appearance.

'What happened?' said Thelesa.

'The barnacles,' said Ferrier. 'They've... gone. Completely disappeared.'

'Yes, they're all feeding in the asteroid belt,' said Locklear, standing in the doorway. She strode onto the deck as though it was just another day at work. 'Thanks to the Doctor.'

'The Doctor?' said Ferrier. 'But how?'

Locklear sighed ruefully. 'He took them out to lunch.'