The tunneling machine came up behind them. The head of a man was wired up inside it.
“That's disgusting.” Lilith gagged. “Is that a corpse?”
Whatever it was, the machine backed them up towards the Tractators.
“Not exactly. There's a living mind enslaved in the middle of that lot.”
“That face. I recognize it from somewhere.” She frowned.
The Doctor nodded. “It's Captain Revere.”
One of the Tractators spoke. “Two specimens have come down to us from the world above in an undamaged state. This is a rare pleasure.”
“Oh, perfecto,” Lilith groaned. “Giant talking termites.”
“How do you do. I'm the Doctor. Oh, er, this is Lilith,” the Doctor said.
“We know you, Doctor, at least by reputation.”
“Then perhaps you won't mind telling us who you are.”
“I am the Gravis. Follow me.” The Gravis led them to a room with a spiral design on the floor. “This is our center of operations. You see, Doctor, I do not fear you will take this information back to Gallifrey. You will never leave Frontios now.”
“Hmm. Well, you could be right, Gravis.” The Doctor paced the length of the room.
“Considering the state of the TARDIS,” Lilith snorted.
“TARDIS?” the Gravis repeated. “You have a TARDIS?”
“Not any more.”
The Doctor went back over to the Gravis. “Ah, not any more than any other Time Lord. You like travel?”
“Only those who have been isolated for millennia truly appreciate the power of mobility. Yes I should like to see your TARDIS. We have been marooned out here on Frontios for nearly five hundred years, as I'm sure the Time Lords already know.”
“Yes, I'd better put you right on one thing, Gravis. The Time Lords didn't send me to investigate. Gallifrey operates a policy of strict non-intervention these days. And besides,” he wandered over to Lilith, “Frontios is completely outside our normal sphere of influence.”
Lilith rolled her eyes. “So basically, you’re telling him ‘Go ahead, do what your doing. I won’t stop you’.”
“We mustn't take the narrow viewpoint, Lilith. After all, Gravis and his friends were here long before the Earth colonists.”
“You’re taking their side? They built the excavating machine! That thing had a man’s head in it!”
The Doctor looked at the Gravis apologetically. “Slight communications problem here, Gravis. My assistant hasn't been programmed in the ways of the world. Please forgive the naivety.”
“Programmed in the ways of the world, my—”
‘Lilith! Silence! I have a plan, just go with it.’
The other Tractator put Lilith in a beam. ‘I cannot believe you are doing this.’
“I'm terribly embarrassed about all this,” the Doctor said.
‘Oh, you better be.’
The Gravis waved its disgusting hand. “Not at all, Doctor.”
“It must be the humidity causing the malfunction. These serving machines are perfectly reliable on Gallifrey.”
“The guard Tractator here will restrain it while I show you more of our work here. It is certainly a very convincing replica of the humanoid life form.”
“Oh, you think so? I got it cheap because the walk's not quite right. And then there's the accent, of course. But, when it's working well, it's very reliable. Keeping track of appointments, financial planning, word processing, that sort of thing.”
Lilith stared daggers at her father. ‘Yes, I’m your limping, American secretary robot. Lovely.’
The Gravis led the Doctor away, leaving Lilith and the guard Tractator behind. Lilith rolled her eyes and sent the Doctor a wave of irritation.
‘It’s not going to kill me, Lilith,’ the Doctor assured her.
‘How do you know that?’ she demanded. ‘You’re in my head, not its!’
Lilith thought she heard footsteps, then thumping, then someone hissing, “Get down!”
The Tractator turns its gravity beam towards the noise.
“It's seen me. It knows I'm here! Help! Help!”
“Turlough!” Lilith shouted. She pulled out her blaster and shot the Tractator. “Tegan! Turlough! Are you okay?”
Tegan helped Turlough to his feet and he nodded. Lilith threw her hands in the air. “Humans and their incessant need to be heroic! The Doctor had a plan!”
“Save the bickering until we're out of here!” said Turlough.
“He's probably in great danger,” Tegan worried.
“Orderlies, keep watch on the Tractator and make sure it stays unconscious,” Lilith ordered. “Brazen! Follow me!” ‘Tegan and Turlough are here. They’re coming for you,’ she informed the Doctor, leading the humans to the main part of the lair.
Brazen ran ahead with Tegan and Turlough.
“No, no, no, stay back!” the Doctor insisted. Brazen didn’t listen and went over to the tunneling machine where Plantagenet was linked in. “Please, there are far too many of them.”
“How do we get him out of this, Doctor?” demanded Brazen.
“Well, theoretically it's highly complex. Practically—”
“No, Doctor!” the Gravis shouted. “I forbid you to touch the machine!”
The Doctor pulled off a linkage, and a bolt of electricity zapped the Gravis. It stumbled around and the other Tractators began stumbling too, seemingly lost.
“What's happening to them?” Tegan wondered.
The Gravis fell on its face.
“Is he dead?” Brazen asked.
“No, no, just stunned. We'll have to work quickly,” the Doctor said. They pulled the linkages off Plantagenet, and Brazen dragged him from the machine while the Doctor held the linkages. “Quick! Come on, you three! We're getting out of here.”
But Turlough just stood staring at the machine, its linkages flailing around seeking a host.
“Turlough! Turlough!” Tegan yelled.
“Come on, Turlough! Pull yourself together!”
Brazen grabbed Turlough, but Turlough pushes at him and he ended up in the seat. The linkages moved quickly, grabbing onto the man.
“Doctor, the Gravis!” Lilith warned.
The Gravis was getting up off the floor. The Doctor was holding back Turlough.
“Get out of here, sir, while there's time!” Brazen ordered. “Go! That's an order!”
Brazen screamed as the machine assimilated its new host. Lilith helped the Doctor drag Turlough out of the chamber.
Plantagenet collapsed against one of the walls and the Doctor knelt next to him.
“Doctor, I remember everything.” Turlough said. “I must tell you!”
“Yes, all in good time, Turlough.”
“I know what they are.”
“And I know what they're trying to do,” said Plantagenet.
The Doctor nodded. “Well, that sounds promising. Put the two things together, we may find a way of stopping them.”
“The excavating machine, it's going berserk,” Tegan told them.
“I think it's time we left. Come on.” The group continued down the tunnels, eventually making it to a naturally occurring cave.
“No sign of them.” Tegan sighed.
“Well, these aren't Tractator tunnels,” the Doctor observed. “We should be safe here for a while. Keep watch that end.” An Orderly obeyed. “Now, what do we know about these creatures?”
“The tunnel system is a gigantic ring, smooth and mathematically precise,” Plantagenet said.
“Yes,” the Doctor agreed. “They're building a gravity motor.”
“A motor?” Tegan questioned.
“That's what they do to planets,” said Turlough. “They're going to drive Frontios.”
“Hmm, steer it through the galaxy under the power of gravity,” the Doctor mused.
“To steal and plunder wherever they go.”
“And breed. Infesting new planets. Nowhere in the universe will be safe from them.” Lilith paused, thoughtfully. “I wonder if we can stick them on Krop-Tor.”
“What’s Krop-Tor?” Turlough asked.
“A planet orbiting a black hole.”
The Doctor scoffed. “Such a planet couldn’t possibly exist.”
“Neither can Satan, but we fought him off too.”
Tegan shook her head. “But if their excavating machine is wrecked, they can't complete the ring.”
“They have another,” Plantagenet admitted. “All they need is a driver.”
Turlough made a face. “And anyone of us will do for that.”
The orderly screamed. Tegan’s eyes widened. “That's the orderly.”
“It's too late! Tegan, wait!” Lilith went after her.
“Lilith, look!” Tegan pointed to a section of familiar roundels in the rock wall, then another section, and a column.
“The TARDIS!” Lilith breathed. “Bits of her anyway.” She spun around to see that the Tractators had found them. She swore in Gallifreyan.
She and Tegan backed away towards a piece of the TARDIS with a door handle on it. The Gravis went up to her. “Perhaps I have been deceived. I think we have found our new driver.”
Tegan opened the door and they dashed inside. Some of the console room wall was rock face, but the console itself was intact.
“Glad you could join us,” the Doctor said. “Turlough, Plantagenet and I have been working out a plan.”
“Well, it had better work because they're right outside,” Tegan panted.
“Oh, I rather hoped they would be.”
“Turlough has remembered the secret of the Tractators,” Plantagenet said.
“Hmm. Apparently they're not really dangerous.”
“It's the Gravis they draw their strength from,” Turlough explained. “Without him, they're harmless burrowing earth creatures.”
Lilith snorted. “They certainly fooled me. So, all we need to do is find a way of isolating the Gravis from the others?”
“That should be fun,” Tegan said, sarcastically. “He's not trying to take off, surely?”
“Unfortunately not. None of the controls are functional.”
“Why would they be?” Lilith sighed. “And, let me guess, me shooting the Gravis would be detrimental to the plan? Even if it’s just to stun?”
“Well, that's it,” the Doctor said. “Now, this should either sort out this whole Tractator problem and repair the TARDIS or…”
“Or?” Tegan prompted.
“Or it won't. I suggest you all get under cover.”
Tegan, Turlough, Lilith, and Plantagenet hid below the other side of the console.
“It is useless to hide!” the Gravis yelled through the door. “We have you completely in our control now.”
The Doctor opened the door and looked out. “Yes, quite.” He stepped outside.
“Out of curiosity, what is it with you and that gun?” Turlough asked.
“Excuse you,” Lilith sniffed. “This blaster had been saving the Doctor’s ass for longer than you’ve been alive.” She paused. “Granted, it technicallyhasn’t happened yet. But my point still stands.”
The Gravis entered the TARDIS. The Doctor followed and shut the other Tractators out.
“The power of travel is beautiful, Doctor. Very beautiful.”
“Yes, yes, indeed. Well, as you can see, from this panel, Gravis, I control all of the main TARDIS functions. The time coordinates, spatial coordinates, all inoperative at the moment, of course, because the spatial distribution circuits are switched in.” The Doctor casually indicated a switch. The Gravis pressed it. “Ah. Now, you really will have to be more careful, Gravis. Now the autoscan's picking up all the locations of the concealed TARDIS components. Oh, well, not to worry. I shouldn't think it's even within your powers to reassemble them. Besides, what would you want with an old Type Forty Time and Relative Dimension in Space machine, hmm?”
“But I do want it, Doctor,” the Gravis said. “The TARDIS. Infinite travel within my grasp.”
“Oh. No, Gravis, please. Take everything else but leave me the TARDIS,” the Doctor pleaded. Lilith rolled her eyes; his acting skills could be improved upon.
“I will have it,” the Gravis insisted.
“Oh no, Gravis, please, I beg you! Spare me the TARDIS!”
“I will have it!”
Turlough poked his head up. “What's he doing, Doctor?” he whispered.
“Shush. This isn't the time to disturb his concentration.” The Doctor pushed his head back down.
The whole area started rumbling and shaking.
“Doctor, what have you done?” Plantagenet hissed.
The Doctor joined them under the console. “Brace yourselves.”
“Are you sure the TARDIS can survive this, Dad?” Lilith asked.
“It's kill or cure,” he responded. The rock faces started to be replaced by TARDIS panels.
“The TARDIS is coming together!”
“For you and me, maybe,” the Doctor confirmed. “But when the Gravis really wants something.”
“The TARDIS will be repaired?” Turlough guessed.
“With a bit of luck, any moment the plasmic outer walls of the TARDIS will seal.”
Lilith’s eyes widened with understanding. “We'll be in our own dimension.”
“If your theory is correct, Turlough, the vital link between the Gravis and his Tractator chums will break. Hold on!”
The lights got brighter, TARDIS walls replaced the rocks and the Gravis collapsed. The light returned to normal and the shaking stopped.
“Is he dead?” Plantagenet asked.
“Oh, no, no, but quite harmless,” the Doctor assured them. “And as long as we keep him isolated from the other Tractators, he'll stay that way.”
Tegan frowned. “We can't go dragging around the universe with a dormant Gravis on the console.”
“Well, the first thing we'll do is drop him off on some uninhabited planet,” the Doctor said. Lilith opened her mouth to suggest something. “Not Krop-Tor.”
The young Time Lady looked genuinely disappointed.
Lilith stood outside the medical center, waiting for the Doctor and Tegan to return from letting the Gravis out somewhere. Turlough had collected the hat stand. “Now all we need is a console room to go round it.”
“Well the Doctor and Tegan are due back any minute,” Range said.
“He's got a present for you,” Turlough told them.
Plantagenet blinked. “A present? But it is enough that he has given us our freedom.”
“Yes, no more terror descending from the sky.”
“Not unless you count the TARDIS,” Lilith pointed out.
The TARDIS materialized. The Doctor and Tegan came out. “Well, that's that. The Gravis is safe and well on the uninhabited planet of Kolkokron, exercising his animal magnetism on the rocks and boulders.”
“There's nothing but rocks and boulders out there,” Tegan said. “All the planets are deserted according to the TARDIS scanner.”
“Well, that's better than being among enemies, as we thought,” Range said with a smile.
Plantagenet was less enthusiastic. “So, the last of mankind is after all quite alone.”
“Alone but in good hands, Plantagenet. Speaking of which, I know it's not much, but, a farewell token.” The Doctor presented the hat stand to Plantagenet.
“Frontios is honored, Doctor. But surely you'll stay a while longer and enjoy some of the new colony we're building?”
“Oh no, no. Far too much repair work of my own to be done,” the Doctor declined. “Besides, time and the time laws don't permit it. There's an etiquette about these things which we've rather overlooked, I'm afraid.”
“But Doctor, you've done so much for us.”
“Yes, quite. Don't mention it.” The Doctor retreated into the TARDIS.
“He means it, literally. Don't mention it to anyone.” Lilith followed her father, followed by Tegan and Turlough. The TARDIS dematerialized.
“Well, this is where I leave.” Lilith sighed. “It was nice meeting you Tegan.” Lilith shook her hand. “Turlough.” She kissed him on the cheek, and then went over to the Doctor.
He smiled at her. “Lilith.”
“The celery,” she said, straightening the celery on his lapel, “it’s kinda cool.”
“Remember this, Lilith. No matter what my previous selves say, and no matter how trigger happy you are, you are my daughter.”
Lilith beamed and hugged him. “Thanks, Dad.” She stepped back and set the coordinates on her vortex manipulator.
In a flash of light, she was gone