Doctor Who - 04 - On a Pale Horse

.10. The Bristol Strain

"So, it isn't a plague?" Donna asked.

They were standing around a high table in a small laboratory, which previously must have been some monk's solitary cell. There was only one tiny window there, too high up on the wall for them to actually see anything outside. A beam of pale light streamed through the window, full of whirling specks of dust that for Donna would always bring back unpleasant memories of Vashta Nerada.

"It was," Kathryn said. "Originally."

"It's mutated," Cuthbert added gloomily.

"No," the Doctor interrupted. "It couldn't have done that. It couldn't have mutated. Not here. Not now. Not on its own."

"Who said it's mutated on its own?" Cuthbert snorted. "Ever heard of the X-Factor?"

"As in the one where they sing and then...?" Donna shook her head. "No. That'd... that'd be... stupid."

"Oh..." Cuthbert snorted again. "Let me introduce you." He gestured towards a small screen located on the table, and touched a few icons on its green surface. A swirly thing appeared on the screen; all smooth lines and pointy outgrowths, and furry halo, and subtle, pastel colours. "Meet the mutagenesis facilitating artificial neo sub-particle X, also called the X-Factor. Isn't it lovely? Our little friend from the future. And the past."

"Thirty second century, to be exact," the Doctor said quietly, leaning over the table top and pushing his 'brainy specs' up his narrow nose. "It is lovely," he admitted. "And it is deadly."

He inhaled deeply, straightening up and sticking both hands into his coat's pockets, but halfway into this familiar gesture he went into a painful fit of coughing and had to bend down again. Donna's hand shot forward protectively. She grabbed the Doctor's sleeve in an attempt of supporting him from falling. The Doctor smiled at her and patted her fingers.

"But it shouldn't be here," he said. "Its manufacturing was forbidden and all the stock was destroyed, by my own people." He turned to Kathryn. "Thousands of years before your time," he finished.

The woman looked at him darkly.

"Some specimens survived," she said. "As they always do. They tend to survive somehow, in some obscure laboratory, out of the beaten track, in some desolate vault, protected by madmen."

The Doctor sat heavily on the edge of the table and tilted back his head, as if suddenly very interested in an arching ceiling. Donna knew he was really very, very angry.

"Humans," he hissed. "You did it again, didn't you? You went and you did it again!"

He jumped off the table and started pacing nervously. "So what happened?"

"There was an outburst of an unknown epidemic in an orbital laboratory seventeen, Glowglobe, the artificial moon of Smutta. By the time my team got there, everybody in the colony was dead. Over three thousand people. Within two weeks." Kathryn said, her voice breaking. "Before entering the base we flushed it with variable-spectrum radiation, making sure everything stayed dead there. And we wore our micro-particle filters when we finally stepped inside..."