'Well, no...' stammered the Doctor, quite taken aback.

'A1, always have been!' barked the Brigadier with an intensity that suggested he was trying to communicate with someone on the other side of the lake.

'Absolutely.'

The Brigadier's face twisted with suspicion. 'I suppose you've been talking behind my back with Doctor Runciman?'

'Brigadier...'

'There's loyalty for you!' the Brigadier ranted on. 'Well, I'm not taking my leave at the funny farm. Nothing wrong, I tell you. Fit as a fiddle. Always have been!'

The Doctor was deeply affected by his friend's distress and determined to root out the cause of his debilitating paranoia.

The Brigadier noticed the Doctor staring at him. He heard his own angry voice as if belonged to another person.

He started his deep breathing exercises.

As swiftly as it had begun, the storm was over.

'Sorry about that, Doctor. Had a bit of bother a while back. Overwork, you know. Doctor Runciman called it a nervous breakdown.'

The Doctor nodded sympathetically.

'Breakdown?' The Brigadier laughed to hide his embarra.s.sment. 'Don't know the meaning of the word.

This one goes on till he drops!'

The Brigadier relaxed. He sipped his tea and began to tell the Doctor something of what had happened to himself in the seven years since he had left UNIT. 'Could have retired on my pension. Grown vegetable marrows and died of boredom in a twelve-month. But then this job turned up. Bit of admin, bit of rugger, CO in the school Corps.'

'Do you teach?'

'Mathematics.' He saw the mischievous glint in the Doctor's eye and laughed. 'I know how many beans make five, Doctor. And you don't have to be a Time Lord to cope with the A-level syllabus.'

'Well, Brigadier,' said the Doctor, putting his cup on the table, 'much as I appreciate your company, I've still got to find my TARDIS.'

It was the Brigadier's turn to look sceptical. 'Your TARDIS, Doctor! I never believed it did half the things you claimed.'

'Just at the moment I'd settle for half a TARDIS.' He grew serious. 'I'm very worried about Tegan and Nyssa.'

The Brigadier frowned and the Doctor wondered if he was about to have another turn.

'I knew a Tegan once,' said the Brigadier.

'Tegan's after your time,' the Doctor interrupted. 'She was travelling with me in the TARDIS.'

The Brigadier didn't hear him. He smiled as if cheered by some private thought. 'An attractive girl. Very high-spirited.' The memory, once released, grew stronger. 'Had an Australian accent.'

'What did you say!' The Doctor was galvanised into attention.

'Australian. Yes, it's all coming back. 'The Brigadier grew more confident. 'Tegan Jovanka. That was her name.'

Clifford-Smith led Tegan through the old stable yard.

'Over there.' He pointed at a wooden hut. Chintz curtains hung at the windows and wild roses grew in a tangle round the door. Someone was pruning the briars with a pair of secateurs.

'Excuse me!' called Tegan.

'h.e.l.lo there.' The man turned. From his military bearing, blazer and regimental tie this must be the Brigadier the boys had said could help her. She was relieved to find he was no Colonel Blimp; quite dashing in fact handsome even.

'I'm sorry to disturb you, but I'm looking for a Doctor.'

Tegan started to pour out her troubles. There's been an accident well a sort of accident. A friend of mine and a boy from the school..

The Brigadier stopped her with a friendly smile. 'I think you'd better come in.' He ushered her through the door.

Tegan entered the room to the strains of the National Anthem. The Brigadier turned off the television.

'Right, sit yourself down, er... young lady.'

'The name's Tegan. Tegan Jovanka.'

The Doctor was wild with excitement. 'It is Tegan!' he shouted.

'That's what I said,' muttered the Brigadier, at a loss to understand the Doctor's sudden enthusiasm.

'Your Tegan, my Tegan - the same person!'

'Of course, Doctor,' said the Brigadier, brushing crumbs from his woolly cardigan.

'Tegan, Nyssa, the TARDIS, they're all here!'

'Are they?'

'Or rather, they were. If you see what I mean.'

'Hardly a hundred per cent, Doctor.' Not for a long time had the Brigadier felt quite such an ignoramus; not in fact since his last meeting with the Doctor.

'I must have miscalculated the offset. The TARDIS came through to the right place but the wrong time-zone!'

The bemused Brigadier shook his head. 'You and that TARDIS.'

'Now it's vital you remember exactly what happened.'

The Brigadier sighed. 'It was a long time ago. Surely what's past is...'

'Very much in the future,' interrupted the Doctor, raising an admonishing finger as if to send Lethbridge-Stewart to the bottom of the cla.s.s. 'You never did appreciate the interrelation of time.'

'Not much call for that in the A-level syllabus,'

bl.u.s.tered the Brigadier, not used to playing the dunce.

The Doctor tried hard to conceal his impatience. He must not confuse the old boy any further for he needed the help of his UNIT colleague more than ever before.

'Brigadier.' He spoke quietly and slowly. 'You have in your memory the information I need to track down the TARDIS and communicate with Tegan and Nyssa.'

The Brigadier had always enjoyed a good crisis - not to mention the company of a pretty girl. He poured a generous measure of his best malt. 'Now calm down, my dear, and tell me about it in words of one syllable.'

Tegan sipped the whisky and relaxed a little. There was something very rea.s.suring about the man who had just introduced himself as Lethbridge-Stewart; resourceful, unflappable and utterly British (she was reminded for a moment of Captain Stapley, the Concorde pilot); the sort of person you could talk to about the TARDIS and who wouldn't turn a hair.

She took another sip and looked round the room.

Everything ship-shape and Bristol Fashion - just like the Brigadier, who was waiting to hear her story.

'A friend of ours and a boy from the school...'

'Boy? What boy?'

'Turlough.'

'Turlough?' the Brigadier frowned. 'I don't think we have a Turlough.'

'So the boy was lying all along,' thought Tegan to herself.

'I'm a new boy here myself,' the Brigadier explained, examining a register. 'Trevor, Trumper, Turner...

definitely no Turlough.'

But whatever the reason for the schoolboy's deception, the Doctor was Tegan's main concern. She had to persuade the Brigadier to organise help. 'They were travelling together when they came down on the hill.'

The Brigadier's att.i.tude changed instantly. 'Came down? Do you mean a plane crash?'

'Well, sort of,' said Tegan, not exactly sure how to explain an arrival by transmat capsule.

'Good Lord, girl. Why didn't you say so before!'

Lethbridge-Stewart prepared to leap into action. 'I'll phone through to our local constable. He can co-ordinate the rescue services...'

'No!' protested Tegan, feeling a bit like the sorcerer's apprentice. 'It's not like that at all. If we can just get some medical help and go back to the TARDIS...' In her anxiety she referred to the machine as casually as if it had been a Mini parked at the end of the drive.

'TARDIS!' exclaimed the Brigadier. 'Did you say TARDIS!'

'Yes, but you don't understand.'

'I think I do, young lady.' He smiled. 'Tell me, Miss Jovanka. This friend of yours, is it by any chance... the Doctor?'

It was a very worried Brigadier who sat, blinking miserably at the Doctor. Little by little his friend had teased the remembrance out of him; but the recall gave him no comfort. Now that he could remember the excitement of Tegan's arrival at Brendon, he was the more appalled it could ever have been forgotten.

'Not to worry, Brigadier,' rea.s.sured the Doctor. 'A simple protective mechanism of the brain. The important thing is to remember everything now.'

The Brigadier looked grim. 'Doctor, you don't know what you're asking.'

'Something wrong?'

'I've been in some pretty tight corners in my time, but unravelling all this...' He was sweating. He felt himself starting to tremble. He was being forced back into the darkness; somewhere ahead was the bottom-less pit. 'I just feel we're on the verge of something really appalling.' He struggled to put his foreboding into words. 'I've never been so scared in all my life!'

Turlough was furious. How dare they lock him in the sick bay. How dare his protector allow it. The Black Guardian was not only evil but incompetent. He s.n.a.t.c.hed the cube from his pocket - but the crystal was dead. Perhaps he should transfer his allegiance to the Doctor; but without the TARDIS its owner, too, was surely trapped and unable to help.

Turlough lay back and reviewed the events of the last few hours. He felt as though he had slithered right down one of those snakes in the ludicrous board game played by Earth children. He also felt very tired. He closed his eyes and was soon asleep.

He must have woken up when the Headmaster slipped into the room, though he was too sleepy to remember how their unusually intimate conversation began.

Mr Sellick was certainly a great comfort. 'There's nothing to be afraid of, Turlough, now that you've explained everything to me.'

'Thank you, sir.' It was a weight off Turlough's mind.

'In fact, I'm very heartened you felt able to confide in me like this.' The Headmaster smiled like a Dutch uncle.

'Though I must say, it's a most remarkable story.'

'But what am I to do, sir!'

'It seems to me you're in something of a moral dilemma.'

'Sir?'

'You've accepted a free pa.s.sage home to your own people, but, to fulfil your part of the bargain, you have to kill this Doctor.'

Turlough thought for a moment. 'But I don't want to kill the Doctor.'

The Headmaster nodded. 'I can see you're in a most invidious position.'

The more he thought about it, the more Turlough felt hard done by. 'Haven't I done enough to separate him from his TARDIS?'