As they walked along it Nyssa asked, 'Take a closer look at what?'

'The Pictogram. There's a ceremony taking place here tomorrow, commemorating the supposed destruction of the Mara.'

'So?'

'The Mara has waited a long time for its return. I think it plans to be - spectacular.'

When they reached the Pictogram the Doctor stood gazing at it absorbedly, taking in the little stick-men, and the dotted lines that ran from their heads to the crystal in the last panel.

'There, look, Nyssa, what do you make of that?'

Nyssa shrugged helplessly.

'Look,' said the Doctor. He pointed to the drawing of the crystal. 'That could represent the Great Crystal, couldn't it?'

'I suppose so.'

'And these lines represent energy of some sort?'

Nyssa nodded. 'Mental energy, perhaps. The lines go from the crystal to the heads of the figures.'

'Minds meet in the Great Crystal,' mused the Doctor. He pointed to the demon figures, lurking in the background of the Pictogram.

'Everything in this pictogram tells us something, if you know how to read it. So - what are these?'

Lon's half-doze was interrupted by a discreet tap on the door. He opened his eyes. 'Who is it?'

The door opened revealing a palace attendant. Behind him in the corridor loomed the inevitable figure of the bodyguard. The attendant bowed. 'There is someone here, my Lord. He insists that he must see you. Shall I send him away?'

Lon considered. Any break in the boredom was welcome. 'No, let him come in.'

The attendant disappeared and a moment later Dugdale entered the chamber looking around in awe, bowing and sc.r.a.ping with every step.

'Excuse me for intruding, my Lord.'

Lon stared at him, and then laughed. 'Oh, the showman!'

'I'm flattered you remember me, my Lord.'

'I remember your impertinence. Go away.'

'Our previous encounter was rather unfortunate, my Lord. Heat of the moment, press of the crowd, various misunderstandings . . . and so forth.'

'What do you want?' snarled Lon.

Dugdale swallowed hard and said miserably. 'I've been sent to fetch you.'

'Have you indeed!'

Dugdale stumbled on. 'Yes my Lord. You are summoned.'

Lon sat up and stared menacingly at the terrified showman.

'Summoned? I am summoned! How extraordinary. By whom?'

The Doctor was on all fours peering at a figure in the bottom of the Pictogram. Nyssa had moved on into the Chamber of the Mara, where she was looking at the great carved snake.

'Doctor!' she called.

The Doctor got up, dusted his knees and came to join her. 'What?'

'If the Great Crystal of the Legend really existed -then, logically, that is where it would have fitted.' Nyssa pointed to the blank socket between the snake's jaws.

The Doctor stepped back, studying the terrifying snake carving. Things were beginning to come together. 'Yes, of course, it's obvious.'

'What is?'

He led the way back to the Pictogram. 'The Great Crystal . . . The Great Mind's Eye. The lines do represent a flow of mental energy, but not going to the figures, coming from them.'

'And meeting in the Great Crystal?'

The Doctor nodded. 'Just as a lens focuses the rays of the sun, the Great Mind's Eye gathered all the individual thought-energies and concentrated and amplified them.' The Doctor indicated the last, blank panel. 'Redirecting them, presumably, there!'

'But it's been scratched out!'

The Doctor turned and strode back into the main chamber. 'Now, according to the Legend, the Great Crystal is the source of the Mara's power. But where is it now? What exactly are its properties? If only I could get a look at the Great Crystal itself. . . unless . . .' The Doctor fished the crystal pendant from his pocket, and stared thoughtfully at it. 'Unless . . . Come on, Nyssa.'

'Where to?'

'Back to the TARDIS. We're going to try an experiment!'

Dugdale paused outside his Hall of Mirrors, waving Lon forward. 'In here, my Lord.'

Lon stared at him. 'Here - in your Hall of Mirrors? I hope for your sake I'm not going to be disappointed?' Lon had listened with amused disbelief to Dugdale's story of a strange girl with extraordinary powers who insisted on seeing him. Some local girl he supposed, drawn by the glamour of his great position, spinning a fantastic tale to arouse his interest. He had decided to go along with the game, just as long as he found it amusing.

Dugdale gave him an anguished look. 'Please, my Lord. She's waiting inside.'

'Can I have your personal a.s.surance?'

'She's inside,' repeated Dugdale.

'So I should hope,' said Lon.

He went into the booth.

A little uncertainly Lon moved through the darkened hall. He smiled when he saw Tegan standing before the mirror. So, there was a girl after all. Quite an attractive one. He advanced towards her. 'You summoned me. It's not something I'm accustomed to, but here I am.'

For a moment Tegan took no notice of him.

'Well?' said Lon impatiently. 'What happens now?'

Tegan turned slowly towards him. He saw there was a reddening about her eyes and mouth. She held out her hand. Lon smiled. It was just as he had expected. 'Yes . . . after all, why not?'

He took Tegan's hand - and was immediately transfixed as a current of energy flowed between them. Frightened, he tried to pull away, but Tegan's grip held him powerless. In the mirror behind him, there appeared the snake-skull of the Mara.

Suddenly Lon relaxed. He looked wonderingly down at his hand, the one Tegan was holding. On the back of his forearm, as on Tegan's, was the design of the snake. The Mara had marked another follower.

6

Dinner with Ambril

Very delicately and un.o.btrusively, the Lady Tanha stifled a yawn.

Ambril's little dinner party had just begun. Various local dignitaries had paid their respects and withdrawn to a discreet distance. Now she was trapped with her host, who was launched into yet another interminable lecture on his favourite, and indeed only, topic of conversation.

Ambril droned on. 'And, then, you see, my Lady, we draw a complete blank. It's quite clear that the Ma.n.u.ssan's of the Pre-Sumaran era were a highly civilised people. Their technology, in some respects, was considerably in advance of our own. And suddenly, almost overnight, the Ma.n.u.ssan civilisation simply disappeared. Evidently it was subjected to a cultural catastrophe of unimaginable proportions.'

By now Tanha was hungry as well as bored. 'Shall we eat?' she suggested brightly.

Ambril was too absorbed to hear her. 'Yes indeed, to such an extent that when the Federation records begin, some six hundred years later, they speak of the Ma.n.u.ssans as a primitive people, in thrall to the Mara, sunk in barbarity, degredation and cruelty.'

Lady Tanha stifled another yawn, a big one this time.

Ambril peered worriedly at her. 'Are you all right, my Lady?'

Lady Tanha smiled and nodded. 'Yes, yes of course, do go on.'

'What a shame your son was indisposed this evening.'

Lady Tanha sighed. 'Yes indeed. I'm sure he would have found it all most illuminating.'

Lon was striding up and down the Hall of Mirrors, staring at the distorted reflections, and laughing hysterically.

'Silence,' said Tegan.

The laughter stopped, as if cut off by a switch.

Tegan turned and walked stiffly out of the door.

Instantly Lon followed her.

By now, Dugdale was wondering what the devil he was getting himself into. Whatever it was, it was too late to draw back now. Miserably he trailed after them.

The Doctor sat cross-legged on the floor of the TARDIS control room holding the Snakedancer crystal between finger and thumb.

Nyssa sat cross-legged opposite him. 'Doctor, I'm not at all clear what we're supposed to be doing.'

'Just think about it!'

'About what? What are we doing?'

'A simple test. If the Great Crystal focuses thought in some way, if this is the same sort of crystal it should exhibit some of the same properties.

So, we must direct our thoughts at it, and see what happens.'

'All right, Doctor, if you say so. Now?'

'Yes. Now!'

Nothing happened.

After several minutes Nyssa opened her eyes, and stood up. 'I'm sorry, Doctor, I just can't seem to concentrate hard enough. I feel so foolish.'

The Doctor was thinking hard. 'Never mind. We'll try another way.'

He fished the anti-dreaming device out of his pocket and began making careful adjustments.

Nyssa watched him puzzled. 'What are you doing?'

'I'm adjusting the frequency - as an aid to concentration. There!' The Doctor slipped the device over his head and slipped in the earpieces.

'Right, let's try again. Now then, you just stay there. Watch the crystal closely and observe any changes. Are you ready?'

Nyssa nodded.

'Right,' said the Doctor. He closed his eyes frowning in concentration.

Nyssa stared fixedly at the crystal. For a moment it seemed as if this experiment too would be a failure. But suddenly the little crystal began to glow, brighter and brighter. . .

Nyssa gasped. 'That's impossible!'

The Doctor opened his eyes and the glow faded.

'What happened?' he asked.

Nyssa told him.

The Doctor looked thoughtfully at the crystal. 'It's only small, of course, but the potential power . . .'

Nyssa couldn't see what the Doctor was so excited about. 'All it did was glow with a blue light.'