Suddenly the oscillating time rotor jammed, causing the TARDIS to buck and rock even more violently.
'You realise', shouted Nyssa, 'that the TARDIS could have been damaged during the fight.' As though to confirm that this was the case, the TARDIS groaned like an enormous prehistorical animal in distress. 'We must try and think what the Doctor would do,' said Nyssa desperately.
'There's only one thing he ever does in situations like this,' said Adric, lifting his hand and delivering the console a hefty thump.
'Brilliant,' said Nyssa without enthusiasm.
But as she spoke, the time rotor began to oscillate and the TARDIS smoothly began to materialise.
Anxiously, they watched as the TARDIS took solid form.
'Shouldn't we hide?' said Tegan urgently. 'The android could be at the helm.'
The Doctor shook his head. 'He would have made a far better job of it.' Slowly the door of the time machine opened and Adric popped his head out.
'Doctor!' he said as he emerged. 'Tegan!' Adric's face bloomed. 'You're safe. You're all safe.' He shook Richard Mace's hands.
'So you made it at last,' said the Doctor sourly.
Tegan looked sharply at the Time Lord. 'Come on, be grateful,' she said.
'If nothing else it's saved us a long walk.'
With more pomposity than he intended, the Doctor said, 'I like long walks,' and disappeared into the TARDIS.
'Wel , I'm pleased to see you,' said Tegan, smiling broadly.
'And I, too, lad.'
The Doctor interrupted their greetings and urged them to hurry.
'Where's the Terileptil?' asked Adric.
Tegan shrugged. 'I don't know.'
The Doctor stood in the doorway of Tegan and Nyssa's room and surveyed the wreckage. 'Well done,' he said, as Nyssa came to join him. 'You did well.'
Nyssa smiled sadly as she looked at the shattered remains.
'I knew the sonic booster would work in theory,' he continued, 'but...' he shrugged '...in practice - that's something else. You were lucky.'
Horrified, Nyssa stared open-mouthed at the Doctor, as he returned to the console room, where Mace gazed about him in awe. Yet another experience no one would believe: a box larger inside than out. A magician's delight!
The Doctor flicked some switches on the console and the time rotor started oscillating.
'Where are we going?' asked Tegan.
The Doctor tapped the console absent-mindedly. 'In search of the Terileptil.'
'Do you know where he is?'
'Not yet.'
The miller's wagon rattled noisily along the cobbled street. The city stank of death, with chalk crosses hastily scrawled on the doors of many of its houses, indicating the huge number of plague-victims.
With difficulty, the Terileptil manoeuvred the horse into a narrow side lane. Somewhere in the distance a woman could be heard sobbing and, like some bizarre descant to the crying, a cat screeched in agony.
The Leader pulled hard on the reins and with a loud whinny, the horse came to a halt outside a bakery. Wheezing from the lack of Soliton gas, he slowly climbed down from the box of the wagon and entered the building. Inside, the wood-burning fires of the ovens roared and crackled, and cast a red glow around the room. Adjusting his cloak to protect his head from the heat, the Leader moved quickly past them and into the shadows, disappearing through a low, narrow door.
He shut the door behind him and leaned against it for a moment, staring ahead at the Soliton machine which was standing in the middle of the floor.
Gratefully he inhaled the room's atmosphere.
Stacked along one side of the smal room were piles of logs used to fuel the ovens.
Around the remaining walls, covering every available space, were hundreds of cages full of black rats. The sight was a sad one, as each rat squeaked pitiably, as though aware of their mission and destiny.
Revived by the Soliton in the air, the Leader moved further into the room, his feet scuffling across the reed-covered floor, and the two remaining Terileptils emerged from the shadows to greet him. Suddenly the air was electric with excitement. They were within reach of their goal. Soon they would be rid of the Earthlings!
The TARDIS hovered over London. On the scanner-screen the Doctor and his party stared at a view of the medieval city beneath them. Suddenly a thin white line appeared and began to travel vertically across the screen.
'Doctor. Will you please tell us why you're doing this?' said Tegan, feeling completely frustrated by his refusal to explain his plan.
'Walt and see!'
Quickly the Doctor pressed several switches on the console and the TARDIS
repositioned itself in the night sky. The view on the screen was now of old London Bridge and the surrounding area.
The Doctor operated a lever and the scan-line appeared again and slowly travelled across the screen. As it scanned Southwark, the line wobbled slightly, the distortion growing greater as it reached London Bridge.
Suddenly, as the line hit a point on the north side of the Thames, it folded into a triangle and started to flash over a fixed point.
'That's it!' The Doctor was delighted.
Tegan frowned. 'Well, what is it?'
'The Terileptil base!'
Adric checked a dial on the console. 'There's certainly something there.'
The Doctor operated the lever and the section of London was rescanned. This time the blip was larger.
'Absolutely no doubt,' he said.
Tegan was beginning to fume. 'Please tell me what you've found.'
'An electrical emission from a piece of highly sophisticated equipment,' the Doctor said, smiling. 'Not something you would expect to find on seventeenth-century Earth!'
He operated the TARDIS's controls and the time machine materialised near the miller's horse as a clock in the distance struck midnight.
Quickly the Doctor and party emerged into the street, Mace still clutching his musket.
'That's an old friend,' said Nyssa pointing at the wagon.
'Indeed,' muttered the Doctor, crossing to it.
The horse snorted, as though in greeting.
'But where are the Terileptils?' mused Adric. 'They could be anywhere.'
The Doctor pointed at the bakery. 'A miller's wagon outside a bakery,' he said, looking at the boy. 'Where else could the driver be. Come on.'
The party cautiously moved to the darkened entrance and the Doctor tried the door. It was not locked. Silently he eased it open and the group entered, to be greeted by a wall of heat from the ovens. Mace cocked his musket.
'Where are they?' whispered Nyssa.
The Doctor shrugged, looking around. 'We need a torch!' he said.
Instantly Mace rummaged inside his tunic and removed a tinder box. In less time than it takes to light a modern match, he had opened the box, struck steel against flint and ignited a small amount of tinder. Quickly he moved to one of the ovens, and lit a bunch of rush tapers. But as he handed the burning torch to the Doctor, Adric walked into a small stool, sending it crashing across the floor. The party froze, listening.
Silence.
Mace returned the tinder box to his tunic and picked up his musket. As he did so, the Doctor noticed the small door at the back of the oven room, and silently walked over to it.
'Do we go in there?' whispered Tegan, pointing at the door.
The Doctor nodded.
Mace raised his musket to the firing position as the Doctor took a deep breath and quickly pushed it open.
Seated at a desk in the middle of the room was the Terileptil Leader, pen in hand, writing.
'Good evening,' said the Doctor, as jauntily as his apprehension would allow.
'Welcome, Doctor,' the Leader said calmly, placing his pen on the table and rising.
The Doctor moved a little way into the room, Mace at his shoulder.
'You appear to be expecting me,' said the Doctor.
'I was expecting my android. But if you've brought the TARDIS here, so be it.' The Leader's pleasantness was beginning to make the Doctor feel distinctly uneasy. 'Please come in,' he said, beckoning with a webbed hand.
'But first put away your gun.'
'You jest, sir!' said the actor indignantly.
The Leader indicated his own high-energy-beam weapon on the table before him. 'I mean you no harm.'
Cautiously, the Doctor and Mace moved a little further into the room. No sooner had they advanced than one of the Terileptils positioned behind the door seized the barrel of Mace's gun and the other grabbed the Doctor, causing him to drop the flaming taper, which ignited the dry reeds on the floor.
Instead of relinquishing his hold of the weapon, Mace stubbornly clung on as he was swung around. As the muzzle of the weapon came in line with the alien's middle, the actor squeezed the trigger and the reptile collapsed.
But Mace wasn't out of trouble yet. Such was the recoil from the gun, that it sent him spinning, Out of control across the room, and into the arms of the Leader. The force of impact caused Terileptil, actor, table and high-energy-beam weapon to go tumbling to the ground.
Meanwhile the Doctor continued to struggle with the second Terileptil, but was seriously outmatched in weight and size, and the Time Lord was soon in trouble. Using his last reserves of strength, the Doctor delivered a massive blow to his attacker's stomach, which sent the reptile staggering backwards.
Seeing her chance, Tegan rushed into the room, picked up the musket Mace had dropped and started to beat the winded Terileptil about the body.
The Doctor stood dazed in the middle of the room, feeling sick and dizzy, as Mace continued to struggle frantically, trying to free himself from the Leader's grip.
Suddenly the burning reeds flared up and ignited the store of logs. Adric and Nyssa snatched up sacks and attempted to stamp out the spreading blaze.
With the Doctor's attacker taken care of, Tegan turned her attention to helping Mace.
Savagely she struck out at the Leader and caught him a nasty blow on the head.
As the Leader let out a loud, shrill scream of pain, the room was filled with a second sound, which instantly brought the Doctor out of his daze.
'Out of here!' he shouted, seeing that the Leader's gun was now on fire.
'Quickly!'
'But the flames,' shouted Adric. 'We must try and put the fire out.'
'There isn't time,' bellowed the Doctor. 'The powerpack in that gun is about to explode.'
The Doctor and his companions fled from the room as flames began to embrace the Soliton machine. The Leader grunted loudly as they departed and began to regain consciousness. The other Terileptils were silent and still: one dead from Mace's musketball - the other stunned from Tegan's attack. As the Leader looked around the burning room, he was filled with despair. He had lost. And soon, he realised, he would be dead.
The fire spread even more quickly as the Soliton machine exploded, bringing down the bakery roof.
Out in the smoke-filled street, Nyssa shouted above the noise, 'Shouldn't we try and help the Terileptils?'
There was a secondary explosion.
'It's too late,' said the Doctor.
As he spoke, Mace began to lead the miller's horse away from the burning building.
'Wait!' shouted the Doctor as he tugged at the tarpaulin covering the back of the wagon, and revealed further ampoule boxes. 'Everything into the flames!' he said, as he snatched up several containers.
Quickly the others helped, throwing the boxes of ampoules deep into the flames. As they worked, a night watchman arrived.
'Fetch a squirter!' ordered Mace. 'Arouse the street.'
The confused man ran off to do as instructed.
With the ampoule boxes destroyed, Mace slapped the horse's rump and the animal trotted off to safety.
'We must go,' said the Doctor. 'Our presence here would raise too many awkward questions.' Mace nodded that he understood, as the Doctor's companions entered the TARDIS. 'Can I drop you anywhere?' the Doctor added. Mace looked at the burning building behind him and smiled. 'Your pace of life is a little too fast for me, sir,' he said. 'I shall stay and fight the fire.'
'Goodbye,' said the Doctor.
Both men shook hands, a little sad that their departure was so sudden and abrupt.
'Wait!' said the Doctor, producing the printed circuit he had removed from the control panel. 'A keepsake,' he said, handing it to the actor. 'Goodbye and good luck.'
Richard Mace gave a final wave as the Doctor entered the TARDIS and closed the door.
'Shouldn't we help put out the fire?' said Tegan. 'We are partly responsible.'
The Doctor started to set the co-ordinates on the console. 'I have a sneaking feeling,' he said with a wry smile, 'this fire should be allowed to run its course.'