The Doctor's meditation was interrupted again, when something bumped into him. He opened his eyes, a crust of ice breaking away from his eyelashes. It was the dimensional stabilizer. He would certainly need that. He transferred it to the hand holding the regulator and reached into his pocket. He withdrew his sonic screwdriver, then reminded himself, "In space, no one can hear you sonic." He put it away, shuffled the console components and pulled a Phillips head from another pocket and began the work of connecting the two components.


The Doctor worked with Simon, looking through his collection of lenses and prisms. "I'm a bit of an amateur astronomer. I use these to get a better look at the planets." They tested different alignments, and brought the candle flame into focus, projected against the wall.

Romana suggested to Dr. Pentagrast, that they place blood samples into several dishes with either glucose or a protein solution in varying strengths. "We find its ideal food source, and give it the perfect environment for development. That will show us whether the germ can be detected in colony form."

Pentagrast liked her idea. "We can use chicken broth for the protein, and I'd bet we have some honey around here. I'll send one of the nurses to collect it."

He sent a nurse off to collect the food items, then took a sharp knife, and bled another patient to collect a fresh sample in several dishes. He called out to another nurse to bandage the patient, then wiped the knife off on his coat sleeve and stuck it back in his pocket.

Romana watched him, thankful that the mask disguised her look of disgust, but said nothing about his sterilization routine. "Where does your cooling machine outgas?" she asked instead.

"Out behind the school. Why?"

"Because if cold inhibits the germ's growth, heat will stimulate it."

Pentagrast understood. "Follow me."

Twenty minutes after Romana left with the doctor, the sergeant returned with his men carrying the TARDIS. "Ah, yes. Set it down here, thank you. I'm afraid I haven't anything in the way of a tip, how about a jelly baby?" He held out a rumpled paper bag, but nobody took any. "Suit yourselves," he said, and pulled down his mask long enough to pop one in his own mouth. He offered them to the sergeant, then to Simon.

Simon picked one out and looked at it, then pulled down his own mask and bit into it. A smile spread over his face, and the Doctor smiled back.

"See?" He shoved the bag back into his coat pocket. "Now, you wait here while I retrieve my lens collection. I believe I have just the thing." He pulled out his TARDIS key and unlocked the doors, disappearing inside.

Simon stepped curiously around to the TARDIS entrance. The Doctor had left the door slightly ajar, and light was emanating from inside. He put the fingertips of one hand against the door and pushed it open.

Suddenly, the Doctor was there, blocking the doorway. "Here we are!" He held out a wooden box, and pulled the door closed behind him.

He walked briskly over to the table, and flipped open the lid. He pulled out lenses in turn, holding each up to the light, and finally selected one. "Ah!" he said, and knocked several of the lenses out of the existing series and plopped his down. He pushed them all together and set the candle in place. The candle flame appeared reproduced on the wall, many times larger, and in perfect detail.

Simon collected the series of lenses and placed them in the tube of the microscope. "I… I think I see something. They're still very small, but I think they're moving. I need more light."

The Doctor picked up the candle and brought it over. "Let me have a look," he said.

Simon stepped out of the way, and the Doctor set the candle down, twiddling with the focus.

"Doctor?" Simon said, looking nervously over his shoulder.

"Hmm?" the Doctor asked without looking up.

"Your cabinet… I don't even know where to begin."

"How about 'bigger on the inside'?" the Doctor suggested.

"Yes! Exactly! And it's so bright, but I didn't see any flames, and there was some sort of machine in there — I couldn't even begin to guess what it does! And how did those men even lift it with all that inside?"

The Doctor chuckled deep and meaningfully. "Shall I let you in on a secret?" He took his eyes away from the lens for a moment. "That cabinet, is a spaceship. Romana and I flew here in it, from out there," he said with a roll of his eyes upward. He went back to scrutinizing the blood slide.

"What, you mean you're from Petrion, or something?"

"A little further away, but you've got the idea."

"So you've seen Centeros from space?"

"Actually, it never occurred to me to look."

"I would give anything to see this planet from out there. I've always wondered what aliens see when they look up at us."

"Well, Simon, if you help me stop this bug killing everyone, perhaps I'll take you up for a look-see."

"I'm going to hold you to that, Doctor."

"That's got the focus!" the Doctor exclaimed. "Oh, my. It looks like I'm not the only thing that's arrived recently."

"What do you mean?" Simon asked. The Doctor stepped out of the way so that Simon could see for himself. He peered through the microscope and gasped. "Are those gears?"

"Mechanical flagella is more accurate, but those are tiny machines called 'nanobots' infecting everyone. That's why the antibiotics had no effect."


The Doctor chanced opening his eyes again, and saw a large piece of wreckage moving quickly in his direction. Both hearts beat once in excitement. It was the distress signal assembly! "Excellent!" he thought. "I have absolutely no use for that."

The assembly was massive, however, and he could get a good push off from it.

He looked around at the twinkling bits of wreckage until he saw, barely recognizable at this distance, just the piece he was looking for. He tied his current components to his back with his scarf, then braced himself. He waited a tense several seconds, then twisted just right and caught the distress signal assembly as it collided with him.

He made sure of his grip, then put the soles of both boots against it. He waited for just the moment when it turned him the right angle, and launched himself with all his might. The assembly moved away in the opposite direction, and the Doctor shot ever so slowly toward the distant component he had spotted. It would take a long time to get there, and he had expended a lot of energy in that moment, so he closed his eyes and resumed his trance-like state.


Later, Romana rejoined them, and the Doctor explained the situation. "That means someone released them on purpose."

"Not necessarily. They could have arrived on a meteor or a derelict spacecraft. Simon, have there been any meteors near the city recently?"

"No," he said thoughtfully, "well, there was something, but that was months before the plague started."

"Yes," Romana said, "but the point is the same. They were programmed to infect, reproduce and kill. We have to program these to self-destruct or something."

"We could do that, yes. But I think I have a better idea," the Doctor said. He disappeared into the TARDIS for a moment, and came back out with a metal cylinder about two feet long, with a conical section on top, and a ring around it that the Doctor was using as a handle. He also had a set of jumper cables coiled over one shoulder.

"What is that?" Simon asked.

"One of the backup power cells for the Tardis console. This will provide the power we need. We will also need a pair of enormous plates at the top of the tallest nearby building for a capacitor. We'll use this to create an EMP and fry them all at once.