The bolts drew back at last, and Sarah pulled open the cell door.  (Behind her the metal panel slid back into place, and the watching eyes disappeared.)  Sarah sensed a flicker of movement and swung round but there was nothing to be seen.  The Doctor shot out into the corridor, and saw Sarah peering over her shoulder.  'What is it?'

'I thought I saw something.  What have you been up to, Doctor?'

'Tell you later,' said the Doctor briefly.  'Come on, let's get out of here.'


Like a spider at the centre of its web, Styggron crouched over an instrument console in the secret Kraal control room below the Space Research Centre.  He touched a control and Crayford appeared on a monitor screen.  'Yes, Styggron?'

'I have just observed a second random unit in the cell area.  It has released the first.  What has gone wrong?'

'A second unit?'

'These patterns were not programmed,' growled Styggron.  'Explain!

'Was this second unit a female?'

'Yes, one of the village section by the looks of her.  Check the control directives, a fault must have devloped.'

'It's not a random unit at all, Styggron - and neither vas the first.  Something quite extraordinary has appened.'

'If they are not random units - then what are they?'

'Space travellers!  The male is known as the Doctor.  He advises the humans on defence.  The female is his companion.  They have arrived in the biomagnetron by error.'

There was a moment's pause, then the alien voice said suspiciously, 'By error?  Or by design?  If this Doctor advises the humans on defence -'  He was interrupted by the howl of the alarm siren.

'The guards have spotted them,' said Crayford eagerly.

'After them, Crayford, after them!  They must not escape!'