The Doctor looked into Maren's shrewd old eyes. It would, he decided, be fatal to lie. 'That may be so, Reverend Mother.

But the life of my friend is in Solon's hands. I'm only certain of one thing. If I don't bring Solon the Elixir very soon, she will die.'

Maren held his gaze for a moment, then nodded slowly.

'What do you offer in return?'

'Anything I can give.'

'You are a Time Lord, are you not? A high-ranking one?'

The Doctor smiled, a little ruefully. 'I was once. Now I am an exile and a fugitive. I have little influence with my people.'

Maren considered, staring broodingly into s.p.a.ce. To the Doctor the wait seemed endless. Then, unexpectedly, she smiled.

'Once again you are fortunate, Time Lord. My humour is good, and at present the Elixir flows freely. Ohica!'

The woman at Maren's side turned and went to a recess beside the bronze gates that guarded the scared flame. She returned with a stone phial. At a nod from Maren, she handed it to the Doctor.

'Thank you, Reverend Mother. Now, if you will forgive me, time is short.'

Maren smiled again. 'There too, we can help you.' She pointed to a spot in the centre of the temple. 'Stand there!'

The Doctor obeyed.

Maren turned to Ohica. 'Form the circle.'

A circle of black-robed young women formed around the Doctor. He looked around at their faces all different, all curiously alike. Placid, serene, agelessly beautiful.

'Like statues,' thought the Doctor. 'Or waxworks!'

He knew that when a woman was initiated into the Sisterhood, her age was frozen at the time she joined. It remained so eternally as long as she regularly consumed the Elixir. Only Maren was the exception. Already old when the secret of the Elixir was discovered, for her eternal life meant eternal old age.

As these thoughts pa.s.sed through his mind, the Doctor realised that the Temple of the Flame had faded from around him. He was back in the Castle of Karn, standing in the reception hall of the Hospice, clutching the stone phial of Elixir in his hand.

'Spot of teleportation,' he thought. 'They even did it with the TARDIS once or rather they will do.'

He glanced quickly at the recess where the TARDIS had materialised. It was gone, of course, lugged away and placed under guard by Hawken's men.

Minutes later the Doctor was striding along the hospital corridors, a surprised Solon beside him, struggling to keep up.

'You made very good time, Mr Smith. It's still afternoon, I didn't expect you before nightfall.'

'I had help. How is she?'

'Much the same. We've managed to slow down the spread of the infection. Drago's with her.'

When they turned into Peri's room, Drago jumped up from his chair.

'No change, Surgeon-General.'

They studied the figure on the bed. Peri looked much the same as when the Doctor had last seen her. Her face was shiny with sweat, her arm red and swollen, and she writhed uneasily to and fro.

'We may yet be in time,' said Solon. 'The Elixir please. I will administer it myself. Doctor Drago will a.s.sist me. If you will stand back, please.'

'Can't I do it myself?'

'No,' said Solon firmly. 'The young lady is my patient.' He held out his hand. 'The Elixir, please, Mr Smith. Every second is vital.'

There was no point in arguing. The Doctor handed over the stone phial and Solon and Drago crowded around Peri, screening her from his view.

'Hold her still will you, Drago?' said Solon. 'She's still very agitated and I don't want to risk spilling any.'

The Doctor saw Drago bend over Peri. A few seconds later, Solon straightened up. He turned and handed the surprised Doctor an empty stone phial.

'I used it all. More than was necessary, perhaps, but she's in a critical state. Better not to take any chances.'

The Doctor looked down at the empty phial. Had he misjudged Solon?

He crossed over to the bed and looked down at Peri. She looked much the same as before.

'The Elixir doesn't seem to be acting at its usual amazing speed. Results are usually instantaneous.'

Solon shook his head. 'The infection was very advanced.

Even with the Elixir, recovery will take some time. There's nothing to do now but wait.'

'I'll stay with her,' said the Doctor.

'Very well,' said Solon. 'I'll check on the patient later.' He indicated a control panel above the bed. 'Use the com-unit to summon help if there's any change for the worse.'

Solon and Drago left and the Doctor sat down by Peri's bed.

He unstoppered the stone phial and sniffed it curiously, then frowned thoughtfully.

He settled down to wait.

Chapter Nine.

Arrival Afternoon turned into evening, and evening to night. To the Doctor's enormous relief, Peri's condition slowly improved. Her temperature went down and her flushed skin returned to its usual colour. Gradually the swelling in the arm diminished by nightfall it was back to normal size. The writhing and moaning stopped too, giving way to an exhausted sleep.

White-robed nurses came in and chased the Doctor away while they washed and sponged her, changing the sweat-soaked nightgown and bed linen and removing the bandages from her arm. When they'd finished the Doctor resumed his vigil. Since he refused to budge, a nurse brought him a tray of food and drink.

Peri awoke early next morning, a little weak but otherwise normal. She demanded breakfast, and the Doctor called the nursing station for a tray.

When the meal was finished Peri said weakly, 'What happened?'

'You got ill. Very ill, very suddenly.'

'How come?'

'According to Solon, you picked up an infection in his secret laboratory. He said you'd die if I didn't get some Elixir of Life.'

'Some what?'

'It's a kind of magic potion, produced here on Karn. So I went and got some.'

'And it cured me?'

'I'm not sure...'

'Well, I'm better.'

The Doctor produced a watchmaker's eye-gla.s.s and examined Peri's right arm, just below the shoulder. 'Aha!'

'Aha what?'

'Two small puncture marks, close together. .'

Peri looked alarmed. 'Vampires?'

'Injections,' said the Doctor. 'And here's a third... The first one's considerably older than the others. So that's how they did it!'

'Did what?'

'I don't think you were ever infected at all. It was all a trick of Solon's to get his hands on some more Elixir. He injected you with something to make you ill, switched bottles on me, then injected you with something to make you better. I suspected the switch from the first.'

'Why?'

'Because of the curious incident of the stone phial.'

'What phial?'

The Doctor took a stone phial from his pocket and handed it to Peri.

'Smell it.'

She took off the top and sniffed it. 'It's empty.'

'What can you smell?'

'Nothing.'

'Exactly!' said the Doctor triumphantly. 'As my old friend Sherlock once said, "That is the curious incident!"'

'Stop being enigmatic, Doctor, and explain.'

'The Elixir has a very pungent smell. Not unlike stewed apricots. This phial was already dry and odourless when Solon gave it to me last night. It's been empty for quite some time.'

As she took in what had happened to her, Peri felt a wave of anger.

'I remember now Drago gave me an injection, just before I got ill!'

The Doctor nodded. 'On Solon's orders I imagine.'

'So Solon deliberately made me ill just to get hold of this Elixir?'

The Doctor nodded. 'Mind you, he made you better again.'

'So what are we going to do about it?'

'Nothing.'

'But he tricked you!'

'Out of a bottle of Elixir? He's welcome to it. Who cares if he re-animates a couple more corpses?'

'He might have killed me!'

'But he didn't.'

'What would you have done if he had, Doctor?'

'Killed him, probably.'

With a shock, Peri saw that he meant it.