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“Dr. Jones; Dr. Smith. Thanks for coming.” Handing back the proffered psychic paper, Dr. Carson sighed in relief at whatever credentials he’d seen there. “We’ve had thirteen new cases today,” he continued grimly, getting straight down to business. The man looked dead tired; Martha wondered how many consecutive shifts he’d taken. “Same symptoms as the others. They start by complaining of chest or throat pain, there are signs of restricted respiration, and then they transition into the stage of vomiting up flowers. None of the test results so far make any sense. I’ve never heard of anything like this. “
“I have,” Martha and the Doctor said in unison, then both looked at each other in surprise.
“How in the world have you heard of it?” the Doctor demanded.
Martha felt herself flushing, but this was no time for embarrassment. “Sometimes medical students read fanfiction,” she said.
“…What?”
“And this sounds a lot like hanahaki disease.”
“Yeah,” the Doctor agreed, seeming impressed. “But how do you know that?”
“I’ve read about it.” Martha shuddered. “I didn’t know it was real, but…”
But then again, she also hadn’t known time travel was real, or witches, or space police teleporting hospitals to the moon. With everything else she’d seen, it was hardly worth being shocked at finding an anime trope come true in Gloucestershire.
She’d never thought much of the trope — the concept of dying of unrequited love always irritated her — but somehow, she thought, it made a bit more sense now. Sometimes, looking at the Doctor, it was all too easy to imagine choking to death on the strength of her feelings.
Feeling breathless, she dragged her focus back on track. Right now, there were patients to worry about. The state of her own heartache could wait.
Dr. Carver, poor man, still looked lost. The Doctor turned to Martha. “You want to explain what causes hanahaki disease?”
Martha discovered that she very much did not want to explain it — especially with the Doctor right there beside her. There was a lump in her throat. “How about you explain it,” she suggested.
“If you like.” The Doctor shrugged. “Hanahaki are a plant species from a planet called Sagittarius. No relation to the constellation. Several different species, really. They’ve developed a symbiotic relationship with the local animals; hanahaki seeds take root in the internal organs, and the flowers produce nutrients that the animals absorb. Codependent in the best of ways; each survives thanks to the other. It’s absolutely brilliant. I love evolution, don’t you?”
He paused. The other two were looking at him askance.
“Ah. Fair enough. Not so brilliant at the moment, I suppose.” He sighed. “Unfortunately, like most invasive species, it doesn’t go well when hanahaki turn up in the wrong ecosystem. The seeds are airborne and invisible, and they’re just trying to do what they’re supposed to do. Problem is, the animals here… well. No offense, but you aren’t evolved to handle it.”
“Animals?” Dr. Carver said faintly.
Martha coughed.
“Humans,” the Doctor clarified. “Sorry. So the question is, how did hanahaki seeds end up on Earth? And the answer is, usually it’s because careless people travel without invasive species filters and don’t bother to clean their boots. Have you had any alien visitors recently? Other than me.”
“Oh,” said Dr. Carver. Martha found herself extremely impressed with the man’s lack of freakout. “Well, one of our nurses knows more about it, but there was the thing with the Atraxi—“
“Best not tell me about it,” the Doctor said hastily. “Knowing me, I was probably there. Let’s not risk the timelines. Anyway, luckily for you, it isn’t the first time hanahaki have spread to the wrong species, so I know exactly how to deal with this. I’ll just need to get some supplies from the TARDIS, pop over to Sagittarius to pick up some wildlife so I can make the transplant, and then…”
He broke off.
“Martha, are you all right?”
She was still coughing, doubled over and struggling for breath.
After a moment, she expelled a rose petal.
That, she thought, was cruelly ironic. It could have been any other flower.
She hoped the Doctor’s explanation was the correct one.