Romana stared indignantly at the rubble.  'What's happened?  Where's the TARDIS?'

The Doctor shrugged.  'Buried somewhere under that lot I imagine.'

'Then we're trapped.  There's no way out.  The guards must be close behind us, they'll be here any minute.'

The Doctor seemed unperturbed. 'K9's guarding our rear.  He'll hold them back.'

'Listen!' said Romana suddenly.  'Someone's coming!'

Footsteps were hurrying towards them.  A moment later Merak peered cautiously around the corner.  At the sight of the Doctor he gave a sigh of relief.  'I hoped it was you.  Listen, where is she?  Where's Princess Astra?'

'Who wants to know?'

'My name is Merak.  The Princess Astra and I are betrothed.'

'Well, all I can tell you is, just before the Marshal arrested us I found somebody - and from the voice it was a young lady.'

'Where?  Where is she?'

The Doctor led the way around the corner.  'Behind that metal door.'

Merak gave him an anguished look.  'Buth that leads to a high-rad zone.  We must get her out.'  He began hurling himself uselessly against the door.

The Doctor moved him aside.  'Just a minute.'  He bent and peered through K9's peephole.  'Can't see anybody.'  He put his lips to the hole.  'Hello!  Anybody in there?'  There was no reply.

K9 appeared around the corner.

'Hello boy,' called the Doctor.  'Any sign of our pursuers?'

'I was able to mislead them, Master.  They are running the wrong way.'

'Well done.  Now then, K9 we want this door open.  But be careful.  There may be a young lady on the other side, and we don't want her harmed.'

'Understood, Master.'  K9 glided forward, activated his blaster, and began cutting a circle around the lock.

Merak looked on amazed.  'What is that thing?'

'Don't worry,' said Romana reassuringly.  'K9 won't hurt you.  He's with us.'

'But who are you?  Are you Zeons, as the Marshal said?'

'No, of course not,' said the Doctor briskly.  'Don't worry, we're friendly.  Romana, keep an eye out behind us will you?'

Romana moved to the corner and the Doctor went on, 'Merak, why should the Marshal want to do away with the Princess?'

'What makes you think he's behind it?'

'Too many coincidences, He didn't even believe those charges he was making just now.  It was all acting.'