"This is the hospital?" asked Rose, incredulously.
She had imagined that the Hospital in the Gallifreyan Citadel would be a grand and imposing edifice, all marble and soaring ceilings, with names of major donors engraved on brass plates. Or, failing that, a glittering marvel of advanced alien technology, all glass and brushed steel. Instead, it consisted of a single, dingy ward room, and had the the appearance of something hastily cobbled together: a crowded ring of mismatched beds, overflowing with patients. A twist of cables led from each bed into a central command station. Rose was sitting on an improvised chair--a packing box--near the Doctor, whose body was encased in a flexible biohazard forcefield. This was a measure against contagion, but, as had been explained to Rose, not a guarantee.
"We're doing the best that we can...under the circumstances," apologised the harried young physician, as he finished examining the Doctor.
"Yes--I'm sorry," said Rose immediately. "I know you're working hard, Doctor...?"
"Dr Caligarian."
Rose was actually quite surprised to get a answer to her question. Finally, a doctor with a name!
His examination complete, the physician directed a swarm of nursebots into action. One sent out a stream of long, silvery electrodes that attached themselves to the doctor's scalp. Another located an arm vein, and inserted a thin probe inside. And so it proceeded: each nursebot seemed to be in charge of a particular organ system. Soon the Doctor was covered in a web of silver wires.
Dr Caligarian sat down at one of the command station consoles, and punched up a rotating 3-D image of the Doctor. After a brief study of the image, he made several passes over the console. A moment later, the Doctor's eyes fluttered open.
"Doctor, can you hear me?" asked Rose.
"Everything's collapsing," murmured the Doctor. "Parallel pressure…"
"Delirium," said Dr Caligarian, soothingly. "Give the antitoxin time to work. Just a minute or two, and he'll be..."
"Right!" The Doctor suddenly sat up in bed, his eyes wide. The nursebots skittered about, rapidly rearranging their wires across him. "I'm the Doctor." He pointed at Dr Caligarian, who jumped. "Tell me what you know about this contagion."
The physician stammered, "Er…well, we've only just worked it out. It's a worm."
"What's your name?" asked the Doctor.
"Dr Caligarian. I'm your physician."
"Hmm...that name makes me think you ought to have a...cabinet? Anyway, a worm, did you say?"
"Worms, yes. Microscopic worms. Parasitic helminths. Millions of them. They enter through the skin, migrate through the bloodstream, and then reside in the gut, secreting a neurotoxin. Then they reproduce and exit through the skin again."
"Sounds very nasty. So why can't you kill them? Use some sort of anti-worm medicine--"
"Well, we're able to block the neurotoxin—for a short while, at least. But eradicating the worms themselves is difficult. Once they're in the gut, they encapsulate far enough from any blood vessels that it's difficult for intravenous medications to penetrate. Any toxin strong enough to kill the worm kills the patient, too."
The Doctor gazed about at the nursebots, the force fields, and the command center. "Correct me if I'm wrong, but I was under the impression ours was a highly advanced technological society. Yet you can't kill a worm?"
"Yes….well…you see, there hasn't been an epidemic on Gallifrey for thousands of years," sputtered Dr Caligarian. "No one on staff has ever had any experience treating an infectious disease, much less a parasite. Until very recently, all I ever had to do was set the occasional broken bone!"
The Doctor gestured towards Rose. "She made a full recovery, in a matter of hours. Explain it, Caligarian!"
"What, the human?" asked the physician, surprised. "I can't explain it...humans have a very primitive immune system, they are vulnerable to bacteria, viruses--"
He was interrupted by the wail of a piercing alarm. Dr Caligarian raced to the command console and punched up another 3-D image. Rose recognised the flickering outline of Councillor Romana. He began tapping furiously, gazing at her life sign indicators with increasing dismay. Several long minutes later, the image stablised and the alarm ceased.
The Doctor sank back into the pillows, murmuring bitterly. "If only I'd been able to get the antidote. If only I hadn't allowed the Master to escape…"
"What do you mean, the Master escaped?" asked Rose.
Wearily, the Doctor recounted the events of the previous evening. Rose listened closely to the story, then observed, "It sounds like he used a transmat beam. Why didn't you just reverse it with your sonic screwdriver?"
"With my...sonic screwdriver?" asked the Doctor, laughing weakly. "The sonic screwdriver opens doors. Picks locks. Drives screws. Other things you might do with a screwdriver, if it were sonic. It doesn't reverse transmatbeams."
"My Doctor could have done it."
"Your Doctor," he said, eyeing her reproachfully. "Hmmm." He pointed vaguely in the direction of his jacket, which a nursebot had packed away in a cupboard. Rose understood the gesture. She dutifully retrieved the sonic screwdriver and handed it to him through the force field.
He fiddled with it for a while, his work punctuated by mutterings of "This is never going to work," and, "It's a screwdriver, for heavens' sake." Finally he pointed it at a spot in the corner of his room.
ZAP!
The Master appeared, collapsed on top of a splendid gold shield. The Doctor stared first at the Master and then, very incredulously, at his sonic screwdriver.
"Told you," said Rose.
"Amazing," he said, gazing at the screwdriver with bright, feverish eyes. "You know...I think I could get this to do all sorts of things..."
After marveling at the screwdriver a few moments longer, the Doctor climbed out of bed, scattering nursebots. He staggered towards the Master. "Your plan seems to have backfired. You've no choice now, you must help us." He crouched down and seized the Master's shoulders, shaking him. "Give me the antidote!"
The Master opened his eyes and laughed hollowly. "The antidote? I haven't got it."
The Doctor stared at him in disbelief. "Only the most arrogant fool would unleash an epidemic and not have the--"
"I didn't unleash it," hissed the Master. "I had nothing to do with it!"
"But...but you confessed!"
"I confessed under i torture /i ! I've been accused of so many crimes, what was one more? I was willing to say anything to make it stop." The Master collapsed again. A swarm of nursebots hoisted him up, and deposited him in one of the adjoining ICU beds, leaving the shield behind.
The nursebots tugged on the Doctor's hospital gown, guiding him back to bed. He began to follow them; then stopped suddenly, gazing at the shield. "Caligarian!"
Dr Caligarian, paralysed by the shock of seeing the Master appear, recovered slightly upon hearing his name. "Yes, Doctor?" he squeaked.
"How did this epidemic start?"
"Oh…well, the very first cases were the entire temporal archeological team—"
"The team that journeyed two million years into our past, and brought back the shield of Rassilon." The Doctor's eyes were shining. "The shield that was hanging in Councillor Romana's office. The shield that the Master was clutching. The 'ultimate weapon' he called it..."
"So it's some kind of bio-weapon?" asked Rose.
"No!" cried the Doctor, swaying slightly. Rose was behind him in an instant, steadying him. "A bio-weapon kills indiscriminately. Rassilon would never have made such a…" He snapped his fingers. "Caligarian! What was that you said about Rose? Her primitive immune system? A primitive immune system might be just the thing to battle primitive parasites! Parasites so primitive, we don't even think to scan for them on the TARDIS biofilters. Parasites that perhaps...perhaps just i happened /i to hitch a ride on Rassilon's shield..."
The Doctor's knees began to buckle. Rose helped him back to bed, and the nursebots reformed their silver web about him. In a weak voice, he continued, "Caligarian, she went through Customs, her blood prior to infection is on file, see what you can..."
"Yes, Doctor, yes! I know what you want," cried Caligarian. "Human, come here!"
"My name's Rose," she said, sharply, as she raced up to the command center.
"Please, sorry, I need some of your blood." As she nodded her assent, the nursebots extracted a vial of blood from her arm. Dr Caligarian snapped it into a rotating machine, then punched up two overlapping images of her blood cells. He stared at the images for a moment, becoming increasingly puzzled. "What are those?" He pointed to a spherical cell packed full of tiny granules. There were only one or two of these cells in her Customs blood sample; but they were everywhere in her current one. "These cells are part of your immune system; they expanded to fight off the infection…but I don't recognise this cell type." He tapped at his console. "Checking the database…and…I don't believe it…yes! YES! Eosinophils!"
"What? What's an eosino--" asked Rose.
Caligarian was literally jumping up and down. "Eosinophils! They used to be responsible for scores of asthma-related regenerations in Time Lords, until we had them removed from our genome."
"And…that helps us how, exactly?" Rose was now utterly confused.
"They only cause asthma in civilised societies, when they can't do their real job." He increased the image magnification until a single cell covered the entire field. "See all those toxic granules? Eosinophils migrate right next to their prey and release them. They attack parasites! Worms! Search and destroy!"
Dr Caligarian turned to his console, muttering to himself. "Cloning...expanding... altering MHC..." There was a buzzing noise, and then he pulled a vial of shimmering liquid from the apparatus. He regarded it for a moment. "Here it is but...I don't know...the species variation might make it as lethal as the worm..."
"Let me see," commanded the Doctor. Dr Caligarian handed him the vial through the force field. The Doctor held it up to the light, shook it slightly, and passed it under his nose, as one might smell a fine cigar. Suddenly, he flipped open the head of the nearest nursebot, snapped in the vial, then used the nursebot's syringe attachment to inject it into his arm.
"NO!" cried Dr Caligarian. "I haven't tested it yet!"
An alarm shrieked. The Doctor's 3-D image flickered wildly on the command console. Despite Dr Caligarian's desperate ministrations, the image flashed and went out.