Warning - contains some graphic content

Something's wrong with the car. I can't concentrate, can't pin it down. My head hurts like hell. The sunlight burns my eyes, even through my dark glasses. My throat hurts; dry, hot, sharp. A cough razors its way up my neck.

Cool, hard, glass touches my lips. Liquid, cold and bland-sweet, spills into my mouth. I gulp. It's soothing.

"Not too much," she says. Who says?

The driver. "Tanya?"

"Small sips," she says, and I recognize that funny not-quite-from-anywhere accent. "Vomiting would be bad."

It's bugging me. I can't get it out of my head. "What's wrong with the car?"

"Nothing. It's working perfectly."

Oh, yeah. That's the problem. "No sound. Too quiet." I risk a blinked glance. "Too big. What car?"

"Mine," says Tanya. "It's a modified Hummer. Electric. A little diesel plant cuts in to recharge the battery."

There's a light vibration, all the way through my bones. Or maybe that's just me? My head is a balloon full of pain. "Sick," I say.

"You'll be all right," she says. "You're not going to die."

"You're sure?" I'm trying for a laugh, but I'm sick and I'm scared and it's not working.

"I'm sure," she says. "A whole lot of other people are going to die. But not you."

That's not very comforting.

***

I didn't pick her up. Men like me don't pick up women like her. I went to the club every Friday night with a handful of friends from work, because that's what you do. Not because I like loud music, bad lighting and expensive drinks.

I know how to dance. I took lessons. I told everyone it was for fitness. The truth was: I secretly hoped that being groovy on the dance floor would make me a hit with the ladies. It might have worked if I'd had the courage to ask someone I really liked to dance, but that never happened.

I was dancing with Donna from the Recombinant lab when Tanya cut in. Donna didn't mind. She thought I was gay, and she only danced with me so she wouldn't look desperate. I didn't give a damn about Donna's opinion, because she liked Nascar and professional wrestling, and thought real men drove pickup trucks. But when I was dancing with her I didn't look desperate either.

Tanya was insanely hot; petite, pale-skinned with white-blonde hair and dark eyes. She wore a skin-tight bodysuit of black leather, with a big, chunky zipper that started at her throat and disappeared -- somewhere low. I didn't have the courage to look. She smiled in my direction, moving with urgent grace through the bobbing, swaying mess of people. She was so pretty that I glanced back over my shoulder to see who she was looking at. By the time I realised there was no-one there, she was already in front of me, one hand on my shoulder, hips swaying.

She smiled again. Her teeth were perfect.

Donna shrugged, and rolled her eyes. Then she pointed to the bar, and mimed getting a drink. I think I shook my head. I don't really remember, because just about then, Tanya put her lips to my ear and said: "I'm going to rock your world, honey."

Her breath was hot. My skin tightened and tingled. I didn't even think to ask her name.

***

"Where are we going?" I'm awake again. It's late now, the long summer sunlight slanting in over her shoulder. It hurts. I turn away, and push my face against the upholstery. My eyelids are hot and rough.

"North." Something cold and hard touches my arm. "Drink," she says. "You need the fluids."

"Don't want it." The whiny tone of my voice is embarrassing, but I hurt too much to care. "Doctor."

She puts the bottle into my hand. "It'll help with the headache."

I drink, trying not to move my head. The stuff is flat and sweet. I remember it from before. With one eye, I peek at the label. "Glucose? Tastes like shit."

"Easy energy," she replies. "Good for you right now."

The sun is warm on the back of my head. I shiver, and the muscles down my spine lock up painfully. "Hospital," I say, when I can breathe again. "I've got insurance. Take me anywhere. This is bad."

"You'll be all right in a few more days," she says. "As long as you rest, keep up your fluids, and don't do anything stupid. This isn't going to kill you. You've got a lot ahead of you."

That takes some thinking about. "You said that before, didn't you?"

"Hold on," she says. "Shit." The car swings sideways, then lurches and thumps up over something that goes under the wheels on her side. It's a big thing, and it sounds sort of soft. We swing back again, and the big car whispers on down the road.

"Yeah, I did say that," she says. "Do you know how long you've been sick, Chris?"

The haze in my head isn't going anywhere. Thinking really hurts. "Is it... Thursday?"

"Tuesday," she says.

No way. But -- I touch my chin. Not just stubble; there's a carpet of short, wiry hair. When did I shave last? "Tuesday? How?"

"You were one of the first cases. If you were going to die, it would be over by now."

"First cases," I mumble. My tongue is thick and cottony. "That doesn't sound good."

"It's not."

***

She didn't exactly move in. She sort of came and went. First I knew of it, she turned up at my apartment with a bulky sports-bag and a smile. When I let her in, she breezed past me, dropped the bag in the living room, and made for the shower. Not a word was spoken until she put her head back around the bathroom door and said: "You coming?"

I didn't need a second invitation.

She told me she was a sales rep for a line of sport and fitness gear, and the job kept her on the move a lot. I told her what I was permitted: that I worked in a government department concerned with public health. She didn't seem interested. According to her, I caught her eye with my dancing, and after that, she just thought we 'clicked'.

That was her word for it. Clicked. I wouldn't know, personally. I guess I never clicked with anyone before. It was good. Really good. There was a lot of Chinese food, a lot of shared music and movies, and a whole lot more sex than I ever had before.

It never really bothered me that Tanya took off for days, sometimes weeks at a time. Maybe it should have. Still, what did I have to compare her with?

***

Dark. It's dark outside. I'm warm. Someone -- Tanya has draped my big Tatonka jacket over me, tucked it in against the seat. My eyelids are sticky and hot, but not so much as before, and I'm thirsty.

"I need a drink," I say. And for a wonder, my head doesn't hurt. I'm tired, but I'm wide awake. There's something else, too. "I think I need a piss."

"Good," says Tanya. The dash lights fill her eye sockets with shadow. "Me too. I'll look for a place to pull over."

I struggle to an upright position. "What about a roadhouse? I think I could stomach some food."

She shakes her head, and I see dark bruises under her eyes, lines of strain around her mouth. "Not a good idea," she says. "I'll find a clear place to pull off, and then," she reaches into the centre console and pulls out a very fucking big automatic pistol, "I'll cover you while you do your business. Then if it's still clear, you do the same for me."

Her voice is matter-of-fact, which is too scary for me. I'm still looking at the gun, wondering where and how and when, and how come she looks so comfortable with it in her hand. I reach out and touch the barrel. "Is that loaded?"

"Useless if it wasn't," she says. "Listen, this disease. You got knocked down early, so you don't know. It's like rabies, but without the long wait. You get it and you're infectious in a day. In three days, it's full-blown. One person in four or so gets a mild version, like you. The other three are walking dead men. But aggressive, like a rabid dog. That phase can last weeks. The virus eats holes in your neocortex, turns you into an animal."

I'm cold all over. "Shit. I -- I can't be here. I've got to get back. They need me."

"We're not going back there," she gestures casually with the gun back over her shoulder. "It's all over. We're headed out to a place I know in Humboldt County. More of a compound, actually: isolated, defensible, stocked and self-sustaining."

What the hell is going on?

***

I didn't lie to Tanya. I just didn't tell her the details. I worked for the CDC in San Francisco, devising rapid-response plans for epidemics we hoped would never happen. Centres for Disease Control, not just one Centre, in Atlanta, the way most people thought. That would have been stupid.

A lot of what I did was classified. A lot of what I knew about some of the uglier diseases came via military research and observation. I tried not to inquire too closely about that side of things.

When she became more than a casual contact for me, they ran a security check on Tanya. I guess she must have passed, because I never heard anything more about it. If she'd moved in with me, made it permanent, there would have been another, more in-depth check.

That job of hers. I never wondered even once why she didn't move in. I was grateful to have her around at all.

***

I'm truly awake now. Bone-weary, but too scared for sleep. We pass a cluster of abandoned vehicles, blocking most of the road. Tanya gears down, and uses the Hummer's low range to pull us along the verge, around the blockage. For the first time, I notice we're towing a box trailer. Tanya's been a busy girl.

It's clear something's gone wrong out there. Abandoned cars. Fires rising red in the distance as we pass. Then there's the radio. The same thing on every channel I can find:

'...remain indoors. Fill bathtubs and sinks with water. Do not open your doors to any person without government identification. Any person with an injury or illness must be considered suspect. Isolate such persons until you are sure of their condition. Persons developing a high fever have the Type One form of the disease. If properly cared for, they will recover. Persons showing symptoms of dementia or aggression have Type Two Neo-Rabies. They must be completely isolated until the disease runs its course. Avoid all contact with any person showing signs of Type Two illness...'

We come to a pull-out It's clear, with a view all the way down to the sea. The moon is up, and visibility is good. Tanya brings the Hummer to a halt, and douses the headlights. "You first," she says. "I'll keep watch."

It's hard to convince my bladder to let go, but once it starts, the stream is a Niagara. Strong, stinking, hot, it pours out of me, splattering the roadside. I look back over my shoulder, but Tanya is watching the road, gun in hand. "Finished," I tell her, and zip up.

She hands me the gun. "Be ready," she says. "It drives just like a gas car. If someone comes, take off as soon as I'm in."

The gun is heavy. "I don't know how to use this thing."

Tanya glances back at me. "You'll figure it out. Believe me." She unhooks her cargo pants, and squats.

No better time. I raise the gun. Her eyes widen.

"Who the hell are you?" I demand. I want answers from her; answers to questions I've never thought about asking before. She's too calm, too organised, too smart. She knows too much. She's scaring me.

She frowns. "Don't point that thing at me. I can't pee."

"I don't care." I pull back the slide, the way they do in the movies. It moves with a heavy, ratcheting sound and a single cartridge jumps out and lands with a dull sound. "Fuck."

Tanya giggles. "Oh shit," she says, and starts to pee. Instinctively I look away, waiting for the sound to stop. By the time I look back, she's already standing next to me. I point the gun at her, but she brushes past me and gets behind the wheel of the Hummer. "You're not going to shoot me," she says. "You can't. That's not how I die."

***

On the world's last sane day, I woke up with a killer headache. Tanya was solicitous. She phoned in to work for me, explaining the situation to Norton, my boss, while I lay in the darkened bedroom with a cold compress on my forehead.

When she came back, there was concern in her voice. "Norton says there's some kind of 'flu doing the rounds of the office," she said. "It starts with a headache."

"Mm," I said. "That's right. I didn't think about it, but Rich had a headache on Friday, and he wasn't there yesterday." I thought about it some more. "Chalinda and David both had headaches yesterday afternoon."

"There you are," she said. "Something's going around." The bed shifted as she sat down next to me, putting a cool hand against my cheek. "You're warm," she observed. "I'm going to rearrange my schedule so I can stay in and keep an eye on you."

"It's just a headache," I said, but secretly I liked the idea. It had been a long time since anyone looked after me. "I'll be fine."

Tanya shifted around, and looked down at me. Her face was sombre, and her eyes were darker than I'd ever seen them. "I'll stay anyway," she said. "I've got a feeling you're going to need me."

I smiled, and closed my eyes. Cue blackness, credits.

***

The car reeks of sour sweat. I would kill for a hot shower.

"Forty-one hours," Tanya says, hunched over the wheel of the Hummer. "That's how long it's been since I slept." She looks across at me. "It's making me a little spacey. What did I say that set you off?"

My brain has been coming back to life. I've finished off one of the disgusting glucose drinks and half of another, and I'm full of feverish energy. "You think you're from the future, right?" I say. Her face doesn't change. "You said the aggressive stage can last weeks. But if I'm an early case and it's only Thursday, there's no way you can know that."

"Maybe I'm a foreign agent," she says. "Maybe we developed the stuff and set it loose on America."

"Except you're rescuing me," I counter. "And that bit about how I can't shoot you because you're not going to die like that. You might as well have cribbed it from a Star Trek episode."

"More Terminator, I thought," she says, and laughs. That's the Tanya I love, right there: pop culture arguments while someone points a gun at her. Wish it wasn't me holding the gun. I put it down gingerly, close by. "You want to know?" she continues.

"Sure," I say.

"The LHC gave us a beacon," she says. "It puts out a cascade of particles you don't know how to detect. A hundred and fifty years from now, we can not only detect them, but calculate the decay rate. Navigating through time is a bitch. It takes a quantum supercomputer, a stupid amount of energy, and without a beacon, you can't fix a target. Without the Large Hadron Collider, it couldn't have happened."

"Okay," I say. "That's plausible, in a science-fiction way. So -- why?"

"Neo-rabies," she says. "Kills three out of four, makes the fourth sick as a dog. Meanwhile, the first three are wandering around, attacking others. What do you think of those odds?"

Seventy-five percent death rate? Not even the Black Plague did that. "Survivors?"

"Once the dust settles, maybe 5% of the human species," she says. Her hands are tight on the wheel, but there's a tremor in her voice. "Can we pull over if we're going to talk? I can't keep doing this."

I nod, and she coasts to the verge. "It took almost a century to put the picture together," she says. "We've got records. Your records. And -- from me, and people like me. I've left time capsules. Sealed boxes in marked, known places. So we know a lot about who lives, and who dies, and how. And we know -- we knew -- that we sent people back to help. And I'm one of them. I help you."

This is stretching my head. "You help... me?"

"You're a hero," she says, and there's not a trace of a smile. "You and your... well, me. We go up to Humboldt to a compound set up by some survivalists. Who didn't survive. We take it over. You'll get some more survivors, and you'll build protocols to keep people alive and safe, and eventually, when the New Zealanders put together the vaccine, they'll come and find us here, rebuilding."

A face, dead white and wild-eyed, plasters itself against the driver's window with a thump that scares the shit out of me and Tanya alike. It's a woman, maybe in her thirties, with dark, straggling hair. There's blood around her nose and mouth. She's got something tucked under her arm, something -- and my gorge rises as I realise she's holding half a baby. "Oh Christ," I say. "Help her, help her!"

I reach for the door, but Tanya grabs me. "What are you doing?" she demands. "She's dead already. Look at her!"

"You don't know that! And you've got a vaccine. You could cure her!"

The look on Tanya's face is too much to bear. Like something has broken inside of her, something irreparable. "It's a vaccine, not a cure," she says.

"I know rabies," I gabble. Outside, the woman beats on the heavy glass window with her free hand, leaving streaks of mud and blood. The Hummer is military pedigree, though. She could pound all day and not even scratch the glass. "The vaccine is given after the infection. Afterwards!"

"We haven't got it," says Tanya. "We didn't bring it with us."

Everything goes cold and twisted inside me. "Why would you come without the vaccine?" The words are out of my mouth before I can stop them. "Why would you let billions of people die?"

"We didn't 'let' anything," she says. "It was already history. Don't you understand? This is already done and over in my time. And it saved us, Chris! The Neo-rabies, the zombie plague -- it saved the whole fucking planet. A hundred and fifty years later we've got dedicated fusion plants pulling CO2 and methane out of the air, making fullerenes, nanotubes, graphenes, carbon fibres, diamond lattice, plastics - you name it. Millions of tonnes every year, and it's still warming up. This world of yours was bullshit, Chris." Her face is hard, her voice rising towards hysteria. "You were killing everything. Everything! Even if we could have saved everyone, why would we?"

Even the crazy woman with half a baby falls silent, staring. And the gun is there, in my hand, before I even realise what I'm thinking. "Oh," I say, the words tripping over my tongue. "Oh my God. It -- you brought it with you. You..." I can hear my heartbeat in my ears, thudding like a hammer. My vision darkens. "You brought it on purpose."

She doesn't even look at the gun. "It's not like that," she says. "There's no choice for us. We had the records. We had the means. We know what happened. We had to play our roles because that's how history is. Time travel is meaningless, Chris," she says, with infinite weariness. "You can't change anything because you never did."

"Seven billion people," I say, and the gun comes up. "That's not meaningless."

"It is if there's no choice, Chris," she says, and looks me in the eye. "You can't kill me. I already know when I'm going to die. The records I left in my own writing go for another sixty years."

I pull the - no.

No. I don't.

I stop, and I think. It's not easy, with the dead-baby woman outside, glaring in over Tanya's shoulder. She's mouthing words, now, or maybe just chewing the bloody rags of her lips. Rabies is a hell of a way to die.

But time travel? Bullshit.

Sure. Tanya believes it. Hell, I almost bought it. But I'm sick, and I'm scared, and she's rescued me. I can be forgiven for falling into her craziness for a little while, with the time-travel and the heroic future.

But that really is crazy. Occam's razor: she's delusional. The disease is real. The disaster is real, and it's huge and terrifying, and my poor Tanya has lost herself in fear and denial. She's feeling guilt that the disease hasn't touched her, and her mind has concocted a story. Or maybe she is sick. Maybe the disease is turning her brain to mush right now.

"Go on, Chris," she says. She doesn't sound sick. She sounds surprisingly calm. "Try it. Pull the trigger. You should. I've killed billions, remember?"

The gun is heavy. I'm getting cramped, sitting sideways in the seat to keep it pointed at her. I don't want to shoot her. And yet - she seems to know so much about the disease. If she was a time traveller, I'd have to shoot her. I couldn't live with knowing about what she did.

Except if she was a time traveller, I couldn't shoot her, could I? And if I did kill her, then she wouldn't be a time traveller. She'd just be a tired, frightened, delusional woman who made the mistake of saving me.

Tanya shakes her head. "I can't stand this any more," she says, indicating dead-baby woman with a jerk of a thumb. "I'm going to drive. We're about half an hour from the Humboldt place. I can manage that much." She doesn't wait for me to speak; just puts the car in gear, and plants her foot.

I could do it. I could shoot her. But only if she's innocent.

"Okay," I say. "Okay." It's my choice. I'm putting the gun down because I want to. I'm putting it away because that's the right thing to do. I could shoot her. There's no time travel. I won't shoot her. It's my choice.

"All right," I say finally. "Make me a hero."

Tanya gives an empty little laugh, and we drive off into the cheap-ass zombie flick end of the world.

---