Terrin had often thought it might be useful to slip in and out of time. And now it seemed to have crept up on him, turned against him.

He sat on the floor with his legs crossed, and tried to be calm.

In St Matthew's, the bell for Hall dinner had rung, echoing across the quads. Bernice saw chattering undergraduates spilling from doors, and she watched them rather longingly from the steps of the Senior Common-room. Rafferty was deep in conversation with Dr Styles, the college President, whom Benny had decided that she didn't like, on account of his pudgy face and narrow eyes. At least the rain had stopped, but it was rather cold, and she wanted to get inside and find out what asperge maltaise asperge maltaise, quails and new potatoes tasted like according to the St Matthew's College chef.

While she was sure no one was looking, Bernice took out the homing device which the Doctor had given her. To her astonishment, its light was winking a deep red and the readings on its display indicated 'Are you all right, my dear?'

Her heart missed a beat and she just had time to slip the device back into her pocket before turning to greet the President, Dr Styles.

'Miss Summerfield, isn't it?' he continued. Bernice did not like his silky-smooth affability. 'So glad you could join us.' He lowered his voice slightly. 'James gets very few visitors, actually.'

'Is that so?' They had begun to process into the Hall. Bernice was looking frantically around for her host, desperately hoping that she was not going to be condemned to sit with the President.

'Oh, yes. Since his wife died, you know, he's been quite lonely. Ah, here he is now '

Thankfully, Rafferty was at her side. He took her arm. In Hall, the begowned multitudes rose to greet the President, and he thumped the table. Bernice watched, intrigued, as an incantation in Latin was spoken by a female undergraduate, and made a mental note to add this to her diary. A few books could be put right when she got back to the 25th century... It was only when they were actually seated in Hall, with the President a comfortable five places away, that she dared to say anything.

'James,' she murmured, 'you know the Doctor's TARDIS?'

'That old police box he's always fussing over? Yes, I know. Never could work out what the precious equipment was he stored in there, but then that's the Doctor for you.'

Bernice decided that now was not the time to tell him that. As her wine was poured by an attendant member of the domestic staff, she whispered, 'It's here. Somewhere in the college, I swear it.'

'What do you mean?'

'The Doctor gave me a well, a device. Oh, gosh, I'm going to have to come clean about all this one day. It... well, he uses it to locate the TARDIS. The box. With me so far? Well, it's currently working its little electronic heart out in my pocket, and the readings show a source less than two hundred metres from here!'

Rafferty met her gaze. He was aware that her eyes were fixed on him in a peculiar, not-entirely sober manner. 'That girl,' he said slowly, 'was talking about a temporal implosion on the front lawn...'

'Coincidence, James? Why does that word go so marvellously well with Doubt?'

'We'll check it out,' he promised.

On the Icarus Icarus, the group in the lab had heard nothing after the initial sounds of conflict. Now they were waiting to find out what was happening.

'Got it,' said Dr Mostrell.

The 2D monitor sprang into life.

They saw the ghosts advancing along the cramped walkways, turning their snouts this way and that as if sniffing their route. They shimmered in a haze of green and red, like the lights Ace and Strakk had seen on Q4.

Party's over,' Ace muttered. 'Ever thought you had difficult neighbours?'

'Ace, get back!'

She didn't know what Strakk had seen, but she dropped automatically. Mostrell ducked after her. From the tube of the ladder-shaft, light was pouring into the lab. The air crackled like burning plastic, and something was making Ace's tongue tingle. It tasted metallic.

The shape gathered its wings. They could see the Time Soldiers clearly now, two of them, sweeping their gasmasked heads and their chunky guns back and forth as they advanced, step by step, into the lab.

Strakk was crouching under a metal lab-bench, barely a metre from the creatures.

'How did they get on board?' Mostrell hissed.

Ace felt the answer coming to her. She knew what the Doctor would say. 'They were always going to be on board,' she said. 'We ran into ran into them them.'

Cheynor was digging his nails into his palms. It hurt, and he was past caring.

'Mr Larsen, did we get that power to the bridge defences?'

'It's tricky, sir, but I think I have some.'

'Enough for a force-field?' Cheynor held his breath.

'Maximum I can muster is eighty per cent.'

'That'll have to do. Hit it.'

'Yes, sir.' Larsen's hand hovered over the console. He exchanged a desperate look with McCarran, but she flicked her gaze back to Cheynor. 'Sir,' Larsen said, 'it won't hold them for long.'

'I know, Mr Larsen. Do it.'

'Yes, sir.' Larsen flicked the switch. 'Bridge force-field engaged.'

There was hardly any sound on the bridge now, as one instrumental panel after another had flickered out of life. The soft whimpering was audible to them all. It sounded like an injured animal.

'Les oiseaux du temps.'

In the chair in the corner, Listrelle Quallem, her arms wrapped tightly around her body, was crying.

'Slowly. Slowly, Ace.'

'What the hell difference does it make, Strakk?' Mostrell snapped. He was edging his way towards the arms locker.

'Shut up,' Ace hissed. 'He's right. Can't you see? They're blind. They're trying to trace us.'

'That's crazy,' Mostrell muttered.

'But if they move through Time... maybe their sensors are bombarded with so much at once that they can't can't see us.' Ace was warming to the theory. 'And that's why we're still alive.' see us.' Ace was warming to the theory. 'And that's why we're still alive.'

Dr Mostrell looked, again. The soldiers were passing slowly along the lab benches, hands sweeping through stacks of equipment as if they were not there. Like ghosts or holograms. The halting, careful movements were, indeed, those of the blind.

'They must be passing through our time-phase at some point,' Mostrell said quietly.

'What are you going to do?'

The medical officer already had his hand in the arms locker. 'I don't know what they are,' he said, 'but a Derenna pistol can't miss.'

Ace lunged at his feet, but she was too late. Strakk's cry of 'No!' went unheard above the whine of the weapon. The beam went straight through the nearest Time Soldier and shattered three retorts on the opposite side of the lab.

The soldiers roared. Their eyes burning, they turned to one another and, in a crackle of energy, fused into one. Mostrell, horrified, let the pistol fall. The new warrior, stabilizing now, lifted his weapon in both gloved hands and aimed straight for Dr Mostrell. There was a rush of unearthy wind like the chill from a crypt, and its force slammed Strakk up against his wall and rolled Ace over and over, limbs flailing, till she hit the helium cylinder with unimaginable pain. Time energy coursed from the warrior's blaster, smashing particles into Mostrell. Ace, horrified, lifted her head against the wind and saw Mostrell stagger. Then, caught in freeze-frame, he flickered with energy, his scream echoing in the primitive screech of the warrior. Red fire burst from his hair. His body erupted with light. And slowly, years were stripped from him like mould from an ancient canvas. His white hair darkened. Ace saw a brief image of a thin-faced young man in the blaze of light, and then a frightened boy, before his body, too small to be seen clearly, dropped to the floor in a cloud of clothing.

Light rushed, ripping Time apart, back into the soldier's body, and he swung on Strakk.

Ace staggered to her feet.

'All right, try me, spook!' she yelled.

The outline was changing again. Before their eyes, the Time Soldier was de-stabilizing. Slipping out of phase.

'He's going,' Strakk mouthed, scarcely able to believe it. The light faded, and there was silence.

Except for the hungry, bawling scream of a baby.

In slow and incredulous realization, Ace and Strakk turned as one to look. There was a bump beneath Mostrell's crumpled uniform, and it was moving.

'Christ,' muttered Ace. 'And I thought moisturizer was effective.'

Strakk glanced at the monitor. It was blank.

'Our only chance,' he said, 'is the shuttle bay. Are you with me?'

'You mean we're not going back to the bridge?' Ace was lifting the remains of Mostrell's jacket carefully with the end of the discarded pistol.

Strakk pushed his grey fringe out of his eyes. 'They'll be right in the middle when it hits the fan. You really want to be there? We have to get off off this ship, Ace.' this ship, Ace.'

Small, frightened eyes looked up at her out of a barely formed face. Two crinkled hands with tiny fingernails reached out for hers.

'And what do we do about the most highly qualified brat in the cosmos?' she asked.

Strakk had one foot on the ladder. 'It's easy,' he said. 'You can bring him, or leave him.' He started to climb the shaft.

'Yeah, thanks for your help, like,' Ace muttered darkly. She scooped up the baby, wrapped in what had once been Mostrell's jacket, but which now resembled a mass of roughspun material. 'Be good,' she whispered, jamming the Derenna into her belt. 'And we may let you meet your grandchildren.' Ace took a deep breath. 'Why did I ever get into this?' She started to follow Strakk up the ladder.

At the top, Strakk checked the corridor, then hauled himself up. Ace passed the baby up to him and he held it. Not awkwardly, either, she noticed.

Ace swung herself up, letting her eyes get accustomed to the even dimmer light here.

'At the risk of being a pain,' she said, holding up her right hand, 'have you forgotten something?' The chunky limiter bracelet on her wrist gleamed under the red lights. 'If I go to the shuttle-bay, I'll be playing Ravel's Concerto for the Left Hand for a living.'

Strakk seemed unconcerned. 'Then you'll have to take your chances on the ship.'

Ace grabbed his spare arm, swung him around with surprising force. The baby started to cry again. 'You're my ticket off this hulk, boy wonder. Get this damned bangle off me, now!'

'I can't. It has a voice-activated neutralizer, and only the captain has access to the code-word.'

'Oh, brilliant. You people think of everything.'

'We might have bigger problems,' Strakk shouted over the bawling of the infant.

Ace looked up and down the corridor. She wondered briefly why the noise of fighting had stopped, and had a worryingly likely theory. 'You know the way?'

He nodded.

'Come on, then.'

The baby had big blue eyes, and they were looking at Strakk in awe as he hurried along, keeping close into the bulkhead. 'If you say Da-da, sunshine,' he muttered, 'you're out of here.'

'We have a massive energy build-up, sir,' called TechnOp Gessner.

'Point of origin?'

There was a moment's silence. 'Here, sir.'

The roaring hit them, and the rush of cold wind knocked Cheynor flying. Light stabbed from the ceiling in a dozen places. Two TechnOps were hurled from their chairs by invisible forces. The light, crackling as if alive, was resolving itself into humanoid forms. Cheynor, shading his eyes, saw the wall-to-wall monitor slashed with interference, and the air was filled with the invisible sound of the alien wings. He heard Larsen yell something about the bridge defences, and then in a hail of phosphorescent energy, the figures stabilized.

Cheynor could hear his own breathing.

The only light seemed to come from the crackles of lightning on the monitor and from the red eyes of the twelve gas-masked figures who stood, guns at the ready, at various points throughout the bridge.

Who is in command here?

The voice, like thunder, seemed to come from the tallest of the hijackers.

Cheynor climbed to his feet. He knew that the eyes of the bridge crew were on him. He spread his empty hands wide, in a gesture of peace.

'We are on a mission to survey this sector of the galaxy,' he announced. The desperation in his voice was clearly audible. 'We mean you no harm,' he added.

It was the best he could think of.

Something told him that, on this occasion, his best was not going to be good enough.

Chapter 12.