'Embarra.s.s me?'

Tanha smiled fondly. 'If you were not amusing yourself last night . . .

having fun while your poor mother was being bored to tiny pieces at that official dinner - well, I shall never forgive you.'

'No, Mother, as it happens I wasn't out having fun.'

'Really? You promise?' said Tanha teasingly. She noticed the hand behind his back. What are you hiding?'

Lon gave her an angry look. 'What?'

'There's something in your hand, isn't there? Show me!'

Relieved, Lon transferred the goblet from left hand to right, and held it out to his mother. She examined it with interest. 'It's antique, isn't it?'

'It's just a cheap fake. I picked it up in the market.'

'Since when have you been interested in such things?'

'It caught my eye, that's all,' said Lon impatiently. 'Mother! I will not have you continually asking questions!' He stormed off to his room, leaving the goblet in Lady Tanha's hands.

She stared after him in astonishment. She knew in her heart that Lon was spoiled, though she also liked to think there was no real harm in him. But the vicious anger in his manner was something new. For a moment he had seemed almost like a different person.

Nyssa spent an uneasy night in the TARDIS. When the Doctor still hadn't returned next day she had decided to go to the palace and look for him.

a.s.suming that the Doctor was (a) in trouble and (b) probably locked up, Nyssa had persuaded a friendly kitchen servant to direct her to the prison area. Now she was moving cautiously through the palace corridors towards it. She ducked back out of sight as a tall, curly-haired young man came along the corridor and turned into the doorway of one of the larger rooms.

Chela found Ambril at his desk, immersed in the study of a tattered leather-covered notebook. He looked up impatiently. 'Well?'

'I've taken our prisoner some food.'

'I hope he's grateful.' Ambril returned to his book, realised his a.s.sistant was still there and looked up. 'Is there something else, Chela?'

Chela bit his lip, and then blurted out, 'I think he's harmless.'

'Harmless? Of course the poor fool's harmless. We'll let him go after the ceremony.'

'He is a doctor . . .'

'Doctor of what?' asked Ambril scornfully. 'I'm sure the man has no academic standing whatever!'

As Nyssa approached the prison area she heard a familiar voice. 'No, I do not want more blankets. All I want is to get out of here. Be good enough to tell your master I want to see him.' A door at the end of the corridor opened and an angry palace servant carrying a pile of blankets emerged. Slamming the door behind him, he turned and walked off in the opposite direction. Pleased to find her theories confirmed, Nyssa headed towards the prison area. On the other side of the door she found a corridor, giving on to a row of cage-like cells with slanting metal bars. Only one of the cells was occupied. Pacing up and down inside it was the Doctor. 'Nyssa,' he said delightedly.

Nyssa ran towards him, clasping his hands through the bars.

Lon came out of his bedchamber. He had washed and changed his clothes and he was wearing elbow-high gauntlets that conveniently hid the snake design on his arm.

Lady Tanha was still holding the goblet, and Lon stretched out his hand.

'Give it to me!'

Lady Tanha handed it over. Lon turned and marched from the room.

'Where are you going?' called Lady Tanha.

But there was no reply. She looked worriedly after him.

Chela was still lingering in the Director's office, and by now Ambril had got used to his presence. He pushed aside the journal and looked up.

'Just look at this, Chela!'

'What is it, Director?'

'The meanderings of another crank - like your friend the Doctor.' He tossed Chela the book. 'It was written by Dojjen - in the months before he decided that his particular line of research was best pursued up in the hills with a snake wrapped round his neck!' Ambril snorted. 'You'll find the last entry of interest - mental health interest, that is! Dojjen addresses what remains of his wits to the question, "Where is the Mara?" '

Chela turned to the end of the journal.

Ambril waved his hand impatiently. 'Well, why don't you read it out?'

Chela struggled to decipher the thin spidery handwriting. 'Where the Winds of Restlessness blow. Where the Fires of Greed burn. Where Hatred chills the blood. Here! In the Great Mind's Eye. Here in the depths of the human heart. Here is the Mara.'

'You see,' said Ambril triumphantly.

'Is it a code, Director?'

'Code? Of course it's not a code. It's nonsense. Pure and simple, woolly-minded nonsense.'

'I'm very pleased to hear it,' said a voice from the doorway. It was Lon.

Ambril rose and bowed. 'My Lord.'

'Good morning to you both,' said Lon pleasantly. 'I need to ask a favour of you, Director.' He glanced at Chela. 'A private favour, if you don't mind?'

'Of course, of course, why should he mind,' said Ambril. 'Out, Chela, out, out, out!'

Chela bowed and withdrew.

Ambril turned eagerly to Lon. 'And now, my Lord how may I serve you?'

Nyssa soon realised that although she had found the Doctor she was powerless to free him.

The cell had a heavy old-fashioned lock, and it was firmly closed. Nyssa rattled the door angrily.

'It's no use, Nyssa, I've already tried that!'

'But this is so stupid!'

The Doctor said wryly, 'The lock's very primitive, you see. Practically a museum piece. No electronic impulse matrix to decode, no sonic micro circuitry to disrupt. Just a crude, mechanical six-barrel lock movement, operated by a very large key. Primitive but adequate - more than adequate actually, since the key is what we don't have.'

'There must be something we can do!'

They heard approaching footsteps.

'Quick, hide!' said the Doctor.

Nyssa looked frantically for a hiding-place, but before she found one Chela entered, carrying a leather-bound book. He nodded to Nyssa as if taking her presence for granted.

'Well?' demanded the Doctor. 'Have you come to let me out?'

'I have brought you this, Doctor. It was written by Dojjen. Look at the last page.'

'I'd sooner you unlocked the door and let me out,'

grumbled the Doctor as he took the book. 'I can't do that.5 'Why not?

Don't you have the key?' 'No, as it happens, I don't.' 'Ambril does, I suppose,' suggested the Doctor casually. 'I imagine he keeps the key in his rooms?' 'Yes, as a matter of fact he does,' said Chela impatiently.

'I thought you'd be interested in Doyen's book, Doctor, but if you can't be bothered . . .'

'No, wait, wait,' said the Doctor. 'Of course I'm interested. The last page you say?'

The Doctor opened the book - and made a discreet 'off-you-go' signal to Nyssa over Chela's shoulder. As the Doctor began studying the book, Nyssa edged behind Chela's back and slipped quietly out of the cell area.

Lon had made his request.

Ambril was shocked and horrified. 'My Lord, I am bound by my oath of office. An oath, dating back to the time of the destruction of the Mara.'

'But you do know where the Great Crystal is?'

'Yes, my Lord. But not even the Federator himself may actually see the Great Crystal. However, may I say how grateful I am by your renewed interest in our antiquities.'

'Well, you know how it is,' said Lon casually. 'With time on one's hand one pokes around. Surprising what one can turn up - like this, for instance.' He held out a carved crystal goblet.

Ambril stared at it in astonishment for a moment, and then took it from him with trembling hands. s.n.a.t.c.hing up a magnifying gla.s.s from the desk he studied it eagerly. He looked up, eyes shining. 'My Lord, where did you find this? Where did you find it? I must know.'

Lon stared at him in mock astonishment, and Ambril said apologetically, 'Oh my Lord, I'm sorry to be so insistent, but you don't realise what a find like this means to me.'

'Is it valuable?'

'It is beyond price.'

'And rare?'

'It is unique, my Lord.'

'How strange! I found a sort of cache you see, a secret chamber. It was when I was poking about in the cave system. There seemed to be lots of things like that, as far as I could see. They were scattered around rather, I picked this one up at random.'

'Scattered?' gasped Ambril. 'But. . .how many?. . .'

'I really didn't count.'

'There were many such objects though, my Lord?' Ambril's voice was trembling. 'Many? Lots? My Lord, tell me!'

Lon smiled. 'Perhaps you'd like me to show you where they are?' he suggested casually. Ambril stared at him, open-mouthed.

The Doctor looked up from Dojjen's journal, rubbing his chin thoughtfully.

'Well?' asked Chela eagerly.

The Doctor tapped the book. 'I see he refers to "The Great Mind's Eye" .

. . When was this journal written?'

'It was the last thing Dojjen did before -'

'Before what?'

'Nothing. Give me back the book.'

'Before he what?'

'Before he danced the Dance of the Snake.'

The Doctor stared at him in astonishment. 'Dojjen? But I thought the Snakedance was banned by the Federation?'

'It was, nearly a hundred years ago.'

'Why were they so against it?'

'According to the Legend, the Return of the Mara could only be resisted by those of a perfectly clear mind. The dance was a dance of purification, in readiness to combat the return.' Chela shrugged.

'However, the Federation held that since the Mara no longer existed the dance was no longer necessary. They banned the lance and drove the Snakedancers into the hills.'

'Why were they so against the dance?'

'Apparently it involved the use of-certain powers.' 'What kind of powers?'

'Mental powers - of a kind easily misunderstood - or misused.' 'Yes, of course . . .'

Nyssa found Ambril's rooms without difficulty, slipped inside and began to search for the key to the Doctor's cell. Since the place was so cluttered, her search was not an easy one.

But she found the key at last, inside a carved wooden box. As her fingers closed upon it a voice behind her said, 'And what do you think you are doing?'

Nyssa whirled round.

There in the doorway stood a handsome middle-aged woman in sumptuous rose-coloured robes, a tiara gleaming in her hair.

Behind her in the corridor was a giant bodyguard.