Two Tegans sat back to back in the black void, both angry, both taking refuge in obstinate silence.

Finally Tegan, the original Tegan said, 'Come on, what are you thinking?'

'Don't you know?' asked Tegan Two sarcastically.

'Maybe I do.'

'After all,' Tegan Two went on mockingly.  'You'll have been thinking it too, won't you?'

'But I asked first.'

'So did I.'

'Oh, stop it,' said Tegan desperately.  'Stop it.  If you must know, I was thinking about ice-cream.'

'Yes.'

'What do you mean, yes?'

'So was I,' said Tegan Two.  'I tried it first when I was three years old, and I didn't like the taste.'

Tegan stared at her appalled.  'But that's my memory!'

'And mine.  Stop it.'  Tegan Two turned away angrily and then said more calmly,  'Look, this is silly.  What are we going to do?'

Tegan looked at her in despair.

The sinister young man's simple trick was proving horribly effective.  So convincing, so identical waa Tegan Two that Tegan was beginning to doubt her own existence.

Perhaps the other girl was real and she herself the illusion.

'No,' thought Tegan fiercely.  'I'm real.  I'm real.'

She remembered what the young man had said.

'You will agree to being me.  Sooner or later.  This side of madness or the other.'

The Kinda guard waved the Doctor and Doctor Todd back into the cage with his blaster, stepped back, relocked the door with an electronic key-card and moved silently away.

'What now?' asked Doctor Todd.

'I don't know.'

'Your friend Adric had a very sudden change of heart.  I wonder what he's up to?'

'So do I.'

'Well, at least he's still free.  I just hope he has more than his own interests at heart.'