For years, there had been a bug in Lupita’s hair.  She had bought the cheap implant as a medical student, and it hadn’t interacted well with her biomonitor or immune-system booster.  As well as changing colour on demand, like they were supposed to, the nanorobots that coated every strand changed with her hormonal profile.  When she was angry, depressed, or stressed, they cycled through colours just slowly enough that people watching did a double-take.

Now a researcher and doctor with a vastly higher salary, she kept it, having decided she needed a reminder that not everything in life could be as ordered as she wished.  Right now, though, she was not in a position to make any alterations even if she wanted to, because she was watching a dying man.  The glass shield muffled his screams, but she could have inferred them from the pustules covering every square inch of his skin or the electrical arcs drawing black snakes between failing implants.  His short brown beard shone with sweat; his thick fingers were clenched.  Lupita was fairly surprised to note that he was not bleeding anywhere, nor had he vomited.  For a man in his condition, he was remarkably clean.

The hospital records sat in the corner, but Lupita didn’t need to look at the tablet to guess the essentials.  It had started with an urgent alert from the man’s biomonitor, telling him to get medical attention.  The hospital’s AI-based automatic diagnostician had admitted him three hours ago, recognising that his condition was beyond the range of antibiotics and antivirals that it was authorised to prescribe.  Lupita had been called to take a look, and had watched his condition deteriorate from a slight cough and a headache to what she now saw.

Blaze didn’t help.  He was standing next to her and she could smell the sweat under his armpits.  He called himself a computer hacker and a biotechnologist; Lupita was doubtful.  Her field of expertise was unaltered human physiology, so she had called for a specialist in cybernetics when the patient’s implants had started to fail.  It was just her luck, she thought, that Blaze would have been there picking up something for a mild case of flu on the same day that Dr. Lavoisier was out.  He had introduced himself succinctly.

“I’m Blaze.  What do you want?”

“I asked for a doctor, Mister Blaze.”

“I’m as close as makes no difference.  Also, not mister.  Just Blaze.  It’s my handle, not my name.”

“What’s your name, then?”

“To you?  Blaze.”

Lupita had buried her anger and, since no-one else had come, shown him into the room.  It was a combination of laboratory and operating theatre, designed for rapid-response treatment of new diseases.  Surgical tools mixed with pipettes and test tubes in sterile bags, which leant against the white box of a DNA sequencer.  Cables ran from this to a series of workbenches, each of which was entirely covered with a touchscreen.  Most of them were powered down, but the few that were active displayed a shifting pattern of blue light as they read the vital signs and scanned the anatomy of the man on the operating table in the center.  Tablets, laptops, and memory sticks, all of them blocky and dark grey, were stacked within easy reach, and a sink with antimicrobial hand gel protruded from the wall.  A hulking black machine with green lights around the edges, bigger than Lupita, stood in the corner.  A rubberised keyboard and small screen jutted from one side, directly underneath an understated silver outline of a deerstalker hat and a pipe.  This was Sherlock, able to simulate human bodies down to the molecular level and predict the effects of a hypothetical drug.

Blaze found his voice.  “How long do you give him?”

“Two hours, and he’ll need four new organs if he does survive.”

“We can clone organs.  What exactly is wrong with him?”

Lupita pressed a key on the operating table and it began to project a yellow, rod-shaped bacterium.  “This is it.  From what I’ve seen, it’s a fairly standard bacterium – resistant to most antibiotics and more virulent than usual, but standard.  I’ve dealt with plagues before, and I wasn’t expecting this to be any different.  A few minutes ago, though, I saw it do this.”  She typed a little more and the projected bacterium started to wriggle through a cartoonish image of a human vein.  “These protein structures here and here connect to the emergency ports on your implants: your biomonitor, maybe muscle enhancements, whatever you’ve got.  It pretends to be a surgeon’s interface tool and uploads a computer virus that shorts them out completely.”

“Let me get this straight.  It’s a biological disease that can infect computers as well as humans?”

“It’s slightly more complicated than that, but yes.”

“You’re joking.”

Unperturbed, Lupita continued.  “Usually, we can put a sensor system in a patient to study how his immune system fights the infection, and then design a booster.  Obviously, this isn’t an option.  All we’ve got to go on are a few petri dishes of blood and bacterium.  I can cure a human disease, but you’re going to have to help me keep his implants from killing him until my antigens get to work.”

“Shit.  Can’t we just get a computer to do this?”

“Are you sure you’re a doctor?  Computers can recognise patterns, nothing more.  They can diagnose and prescribe far better than a human.  No computer has ever yet been able to come up with an original medicine.”

Blaze nodded slowly.  “Do we have any idea what this bacterium uploads?”

“His biomonitor went into emergency mode.  It’s been uploading everything it knows since he arrived here.  The virus should be in there somewhere.”  Lupita fetched a laptop from a charging rack and slid it across the table.

Blaze allowed his eyes to drift across the readouts.  At the beginning of the third page, he sat up very straight and pulled the computer closer.  His eyes gave Lupita some idea of where his handle came from.  He smelled a challenge.  “Is this internet-linked?”

“Of course.”

“Perfect.”  Blaze’s voice trailed off as he pulled a wire from his forearm.  He plugged it into the laptop and his fingers blurred over the keyboard.  Lupita, used to dealing with specialists and generally tolerant of their idiosyncrasies, busied herself with the latest test results.  They were not encouraging.  She had begun expecting to synthesize a cure fairly easily, but Sherlock had told her that her first few attempts were toxic in ninety per cent of cases.  This one was better, only poisoning seventy per cent of the three hundred simulated bodies.  On the plus side, it did wipe out the bacterium.  Cursing under her breath, Lupita entered the commands to run the tests again but using chlorine instead of fluorine.  She envied Blaze, whose entire mind was filled by his neurological link with the laptop.  She had to ignore the man on the table on her own.

Blaze slapped the table.  “No dice.  The program’s encrypted,” he said, without bothering to check whether Lupita was listening, “and I can’t find the loader module.  Basically, all modern computer viruses are scrambled to prevent anyone finding out what they do and stopping it.  They all have something that unscrambles them so they can work.  I can’t find it.”  He paused and narrowed his eyes.  “If this is designed to run on implants, the code isn’t going to be too strong.  Implant processors aren’t very powerful.  What’s the access code for your supercomputer?”

“Mr. Blaze, that is a highly specialised piece of biomedical equipment.  It was built to do drug prototyping, not some kind of code cracking.  It would be like hammering a nail with tweezers.  Out of the question.”

“Not Mister.  I never met a computer that I couldn’t boss around.”

“You’ve met one now.”

Blaze grunted a bit and resumed pummelling the keyboard.  Sherlock dinged.  Chlorine didn’t work any better than fluorine.  Lupita told it to try bromine and iodine.  The room filled with the click of keys on two keyboards and the sound of a man swearing under his breath and a woman pretending not to.  Blaze eventually slumped back again.

“Have you made any progress yet?” asked Lupita.

“Some.  Not lots.  It looks like the loader is actually biological.  The bacterium decrypts the virus.  I could really use a simulator or something, to show me how it does it.  Where would I find that?”

“Not here.  If you want a Sherlock, apply for a grant like everyone else.  I’m using this one to develop a lifesaving drug.”

“And I’m not?”

“Let me be very clear about this.  Sherlock has more important things to do with its time than pander to your whims.  I cannot work without it; you can.  So work.”  Sherlock made a sad noise and lit up red.  “That goes double now it’s broken.  I’ll have to restart it.”

“No you won’t.”

“Excuse me?”

“That’s a Sherlock Mark II.  I did some work on something similar to get into a commercial biolab.  Here.”  Blaze poked at his laptop for a few seconds and Sherlock’s lights turned green again.  “You wouldn’t believe how insecure these things are.”

“What kind of work?”

“I could tell you, but then I’d have to kill you.”

Lupita made a strangled sort of grunt and turned back to Sherlock.  “If you’re so good, why ask me for the access code?”

“Always easier to do things politely.”

“How long do you want?”

“Twenty minutes.  No more.”

Lupita stepped away from the display.  “Fifteen.”

Thirteen and a half minutes later, Blaze was done.  His laptop screen filled with line after line of decrypted computer code.  “Tough one.”

“Can you do it?”

“No.”

“Why not?”

“Have a look at this.  It looks very random, almost biological: just the sort of computer virus that a bacterium would evolve on its own.  You see this, though?  This part?”  Blaze indicated a point on the screen.  “It’s far too ordered.  This one line obeys six different computer science best practice rules.  It’s written by intelligent programmers, for intelligent programmers.  The odds against that evolving are impossible.”

“But it evolved, didn’t it?”

“I don’t think so.  I can generally take a good guess at who wrote a particular bit of code.  It’s clearly malicious, but it’s too well put together to be casual criminal.  The professional kind don’t attack implants; there’s very little valuable data stored on them.  That only leaves one option.  This is military, no doubt about it.  That means it’s a bioweapon, and that means I can’t touch it.  I might trigger something that makes it double its reproductive rate or start excreting cyanide.”

“Stop messing around and tell me how to beat it.”

“You don’t beat a military virus, you survive it long enough to restore from Backup.  Just look at him!”  Blaze gestured to the patient.  “Do you honestly think that something like that can just be cured?  No.  Military systems are as good as mine, maybe better.”

“Forgive me if I’m ignorant, but I don’t hear that as a ringing endorsement.”

“Oh, I’m good.  I’m good enough to know that you never wanted a hacker in the first place.  You wanted someone to pass you your test tubes and fawn over you and cry at each new diagnosis.  I’m sorry if I’m not that person.  I thought we were just about to start getting along, and to be honest I was looking forward to it.  The instant I say something you don’t like, we’re back where we started.  I’m sure Sherlock can run a chatbot for you if you want that kind of companionship.  Oh wait, I forgot – it’s got better things to do with its time, doesn’t it?  In case you didn’t realise, we are fighting something new and deadly, and right now I suggest you take all the help you can get.  If you don’t want me, I can go home.  I filter the air there, to keep the dust out of my computers.  I’ll be safe and you won’t be able to send any bugs to get at me.”

“Do you really think I’m going to send bacteria at you?  I could.  I’m just as good as you.  But I won’t because I’m a doctor.  I help people.  All you’ve ever done is take their money.  I can’t believe this.”  Lupita’s hair turned blue.

“Wait.  What was that you said?”

“I said that you were an idiot and a criminal and–”

“No, what was that you actually said?  That you could send bacteria at me?  You could actually do that?”

“Yes, I could, but what does that have to do with anything?”

For answer, Blaze turned back to his laptop, cleared the screen, and started a program from scratch.  “Whatever it is you have to do to make bacteria, do it.  If this thing can work with computers, it’s got its own computer built in.  If it’s got one of those, I can hack it.  I told you.  I’ve never met a computer before that I couldn’t boss around.”

“We’re going to make another bioweapon?”

“Yes, but this one’s only going to work against these bacteria.”

“And what if it doesn’t?  What if it’s even worse than this one?”

“I don’t really see that we have much of a choice.”

“You know what this is, Mr. Blaze?  It’s chemotherapy.  Pour toxins into someone in the hope that the bad dies along with the good.  I read some leaked documents a few years ago.  They’re using those drugs in torture chambers now.  They work, too.  This isn’t medicine.  It’s far too dangerous.”

“Not Mister!  They said that about AI GPs, implanted biomonitors, and DNA scans for personalised antibiotics.  Think of this as the next step.  You’re supposed to push the boundaries, so push them!  No-one ever saved anything by being a coward.”

“I don’t build killers.”  Lupita’s hair was pure white.

“Don’t give me that.  You kill things all the time.  Think how many innocent microbial lives you’ve snuffed out.  If pathogens were people, you’d be public enemy number one.  Luckily for you, they aren’t.  Now, are you going to help me save this man or are you going to play with your sequencers until he explodes?”

“I don’t have any experience with offensive technology.”

“I’ve got enough for both of us.”

Lupita pressed a few buttons on Sherlock’s screen and it began to hum more purposefully.  Blaze pulled a wire from another implant.  He would later complain, only half in jest, that while he did most of the work, Lupita seemed to use up much more lab space with pipettes, DNA sequences, enzymes, bacterial cultures, and Sherlock.  Lupita would counter that at least Sherlock still worked when she had finished with it; it didn’t take Blaze long to begin to wear out the keys on the laptop.

Blaze broke the silence first.  Lupita would have preferred it if he hadn’t done so with an obscenity.  “What if it mutates?”

“It’ll just turn into another bacterial superbug.  There’s thousands of them.  That’s why we all have immune boosters.”  Lupita didn’t bother looking up from the workbench.

“No – what if it mutates its computer interface?  What if it accidentally manages to talk to implants?”

Lupita stood bolt upright and repeated Blaze’s obscenity.  “We can’t use this.”

“Is there a way to stop it mutating?”

“No.  Any reproduction has a risk.  Why didn’t I think of that?”

“If it helps, computer scientists haven’t been able to fix this either.  The internet mangles data all the time.”

“Why doesn’t it come up mangled on my screen?”

“The computer looks through each incoming block of data for errors and asks for a new copy if it doesn’t seem right.  It’s called integrity checking.”

“Integrity?”

“Yes.  Are you all right?”

Lupita punched a DOI number into a workbench from memory.  “I read a paper once on this, for my Ph.D.  It was wrongly cited somewhere else and I had to spend a day tracking it down.  You don’t forget something like that.”  The bench filled with text.  “Vaughan et al., Cellular Integrity Verification.  They made a kill switch for mutated DNA.”  She scrolled to the next page.  “It’s never been used in a production bacterium before.  Vaughan had a reputation for maverick research.”

“Sounds fun.”

“It’s dangerous.  On top of that, I don’t know if it will work in the human body.”  Lupita drummed her fingers on the workbench.  “Let’s do it.”

“Just like that?  No eighty-page cost-benefit analysis?”

“Quiet.”  Lupita copied and pasted a swathe of the paper into Sherlock.  “What do I upload?”

Even Lupita later admitted that pondwater green was not a good colour for medicine.  The injection became active within minutes, but they felt like hours.  The biomonitor display on the operating table flashed once, reporting a slight decrease in the level of infection.  Slowly, and then faster, it began to flash continuously as the new bacteria carried out a genocidal war against the old.  Lupita’s hair turned violet in relief.

“I think we got away with that.”  Blaze summed up the situation.

“You know,” said Lupita, “we’ll need to give this a scientific name.  Any ideas?”

Blaze pondered for a moment, let down for the first time in his life by his near-complete immersion in hacker culture.  “Nothing printable.  You?”

Lupita told him.

“No.  Something else.”

“I don’t hear you coming up with anything.”

Blaze never did manage to think of something that he found both catchy and polite.  When the time came to write up the research, he was long gone anyway.  He did read it when it was published, though, and was forever annoyed that he hadn’t been able to stop Lupita calling their invention calculatiobacterium misterblazeii.