Some say the world will end in fire,

Some say in ice.

From what I've tasted of desire

I hold with those who favor fire.

When I was a child, I knew how the world would end.

I crouched under my desk with my hands over my neck and I knew that someday the air raid sirens would go off and it wouldn't be just a drill. Someday the Communists were going to drop the Bomb, the Big One, on us, and I was going to be ready, but that would be the end of the world as I knew it.

When I was a young man, I knew it was only a matter of time.

Ronald Reagan talked about a defense system in space that would shoot down missiles from Russia, and I thought about Bert the Turtle for the first time in twenty years. I had friends who were nuclear physicists, I had contacts in the military, and I knew that what would happen when the end finally came would be singularly terrible, and no amount of hiding in a fallout shelter could save me.

And when I was older, I knew it would be my fault.

I dreamed of the burning world and the steady tick of Geiger counters, and in the waking world I knew that it wasn't the Communists who were going to bring the end, it would be people I knew, companies I had worked with. I would see people I had loved die, and I would be helpless to stop it. There are no filmstrips about not making deals with unethical corporations, no cartoon characters to tell you what to do.

But you deal with it the same way, the only way there is:

You sit, and you wait to die.

Peyton screamed, "I can't see! I can't see, Mommy. Mommy, where are you?" Her eyes were wide, her face tear-stained and mottled. Arms outstretched, she was moving across the porch with tiny, stiff, uncertain steps.

When I was a boy I borrowed my father's copies of On The Beach, and Alas, Babylon. I remember sitting on our back porch, my fingers black with ink, thinking about the filmstrip my teacher had shown the class earlier that week, and feeling sick to my stomach.

I thought about a window sash swinging in the breeze, about a flash-blind girl my age screaming that she couldn't see, about somebody making a mistake and ending the world, and I thought that maybe I didn't want to be a scientist anymore.

Eventually I got up and snuck the books back onto the shelf in my father's den, but when I closed my eyes that night I dreamed of watching a big ungainly bomber moving slowly across the sky, and a great white cloud blooming on the horizon.

And many years later, when my daughter was small, a colleague loaned me a CD with a game on it. "I think you'd like it," he said, and gave me a friendly pat on the shoulder. "Let me know what you think."

At home that night, when I finally made my personal computer run the file, I found myself surprised - it started with an animation, stuff that looked like it was from the science-fiction magazines of my boyhood, and a song that I recognized.

It played for almost a minute, and as the picture zoomed out to the ruins of a city, I saw that I had stopped liking science fiction when I realized I was living it.

Maybe you'll think of me

When you are all alone -

Maybe the one who's waiting for you

Will prove untrue -

Then what will you do?

I think they called it Ice-9 when they were developing it. Some kind of laboratory in-joke that relied on a very particular detail of its activity.

Ice-9 was a child of the old Soviet biowarfare program, that house of nightmares. The prodrome is similar to many illnesses, including, ironically, radiation poisoning - nausea, vomiting, headache, fatigue, fever, skin reddening. Then it becomes something like what we used to call a filovirus - victims completely fall apart, bleeding out from every orifice of the body. Every system is attacked, every system fails. There is no vaccine, and there is no cure.

They called it Ice-9 because when it met human cells, it tried to make them into more of itself, like ice-nine did when it met normal water. Hilarious. Most lab jokes are of about that caliber.

Its main interest, other than its facility at killing, is something I only recently discovered myself. I think they must have known when they made it, but none of that team has survived.

Every artificially-created organism alive now shares a specific sequence of DNA that baseline humans do not possess. It adds a tiny receptor on the surface of their cells that is normally closed, but responds to the presence of a specific chemical cocktail by opening and initiating mass cell death.

It's a kill-switch.

But Ice-9 does not recognize cells that bear it. It passes them by. If my daughter were exposed to Ice-9, nothing would happen to her, because of those tiny cellular tags.

Then something happened. I don't know if it was intentional, or a freak mutation. But Ice-9 had previously only been able to spread through direct blood transfer, and suddenly it gained the ability to spread via aerosol. Through the air.

I think they found out, the team that made it. I think that's why they put it in a freezer in Russia for twenty years, sitting in a vial in a rusty can of peas. I think that if you looked at their reports, you would find that all of a sudden they deemed the project a failure, destroyed all samples but one, and froze the remnant.

They didn't want Ice-9 to ever be used. The Soviets had smallpox and a thousand other diseases sitting on ice in case war broke out. At least you can vaccinate for smallpox. If you get Ice-9, you're a dead man walking.

The worst thing that can happen to a forgotten disease is for it to be found again. Especially this one. I think you know who found it, or at least who's claiming credit.

One of my friends in Germany let me know when that happened - he's one of the recipients of this document, if he is still alive, and I think you are, you wily old bastard.

You were wrong. I want to rub that in. They were going to release it. They knew it would kill them, too. They just didn't care.

I could've just sat down then and waited for the end. In some ways I've been doing that for fifty years - whiling away time, waiting for someone to end it all.

But you know me. If you're alive and reading this, you knew me. I couldn't resist the urge to tinker.

My friend in Germany sent me something else - a sample of Ice-9. I don't want to know where you got it (and in any case, by the time you reply I won't be here to read it, though I know you'll want the last word just on principle). Thank you, though.

I had some time. I grew cell cultures from our samples, and I began to ask - what would happen if one of our artificial organisms caught Ice-9? There were so few of them I had time to try them all.

If you're reading this, I'm happy to tell you - almost all of you are, indeed, safe from Ice-9.

Almost.

Fang, you're different. I didn't work personally on your genome. Someone else did, and something strange happened during your creation. I don't know if it was intentional or not, but you bear a unique stretch of DNA that no one else does. It's relatively small, just 500 nucleotides. Whatever it was meant to do, we'll never know.

What it does is a different question.

When I cultured your cells with Ice-9, I saw something very, very bad happening.

Ice-9 has an Achilles heel. Once it kills cells, it begins to degrade very quickly - the proteins of its coat begin to denature in hours, unless it finds a new host in which to replicate. If it doesn't, it falls apart. About a day after a person dies from Ice-9, you can handle their tissues bare-handed without risk of infection.

But not if it passes through your cells, Fang.

You're not completely immune to Ice-9, but you would show no symptoms. You would be a carrier. The tiny protein that those 500 base pairs code for interacts with Ice-9 in such a way as to tame it, to change it.

When Ice-9 interacts with your cells, and specifically with that special protein, its own protein coat begins to change. It becomes stronger. Something in the structure changes.

Ice-9 hides out in your cells. Some of it sheds and enters the environment, but not in the volumes it does when its usual victims crash and bleed out. It waits a while, and on some signal, it leaves again. Usually when Ice-9 leaves a cell, a kind of count-down clock starts until it begins to degrade.

When Ice-9 leaves your cells, it never degrades. I don't know what it does specifically, but I know that a sample I kept isolated for a week successfully infected and killed a sample of baseline-human cells. That's seven times longer than the usual safe time for Ice-9.

This is the key that your DNA holds. Immortality.

For a virus, anyway.

I don't know how much you know about the way diseases spread, but that is a very dangerous thing. It means that once Ice-9 passes through your system, it becomes unkillable. It can hide forever.

Ice-9 doesn't kill all its victims. So far the percentage has been around 90%, higher in some places. Reinfection is invariably fatal.

This is the thing that is dangerous: given a way to be immortal, Ice-9 doesn't have to die off after it strikes 90% of us and a day or two goes by. It can wait. It can afford to be patient, to come back in a week, a month, years.

Fang, if you catch Ice-9, you would end the human race. Not immediately. But within a few decades at most, you would be all that's left.

I'm telling you this so that you know why I tried to do what I did. You can do what you want with the knowledge. I wish you didn't have to know.

Maybe you'll sit and sigh,

Wishing that I were near.

Then maybe you'll ask me to come back again

And maybe I'll say maybe.

When you are exposed to very high amounts of radiation, there's a period of time before the symptoms start to show. You walk around, feeling normal, looking normal, thinking you're lucky that you didn't die instantly.

They call this the walking-ghost phase. You're already dead, your body just doesn't know it yet.

Ice-9 has a walking-ghost phase too - usually about a week, but as long as three.

This used to be a military base before it was handed off to us. If I had to I could hide out here until Ice-9 dies out - assuming it does, assuming it never reaches Fang wherever he's hiding out.

Assuming.

But when I think about it, I don't want to huddle in a bunker waiting until it's safe to leave. And when I look at the monitoring equipment, I see signs that someone's still alive in China, and that they're finishing the job they started a week ago of eliminating US government outposts.

I kept a bottle of bourbon in the bottom drawer of my desk - a gift from a friend who believed that no desk should go without medicinal alcohol. It's sitting on that desk now as I write, next to a glass from the cafeteria with melting ice in it.

The monitors tell me I have about twenty minutes to impact. They tell me impact will be very close by, but they assure me that if I proceed in an orderly fashion to the shelter in the basement of this building, I will be protected not only from the blast, but from the fallout. Then I'm to wait for further instructions.

I don't think I'm going to do that.

When I first detected imminent launch, I told the few remaining interns where that shelter was. I gave one of them my access card and told him the override codes - a young man with one arm who I hope never has to read this but I know will. Reilly, I told you not to open this file. I don't care if it is backed up down there.

I'm not going to join them. I'm done.

For a while I was sure that someone was going to assassinate me. Someone tried. Then I was sure, more recently, that Ice-9 was going to kill me. It's not going to get the chance.

So I'm going to finish this file and send it out. There aren't many recipients, but I hope at least one of them reads it. I spent a lot of time on it, and there is, among my last thoughts, some good information.

Incidentally, Fang, because I know that if you opened this, you got impatient and scrolled to the end, please download the text file attached to this message. It contains some information on a chemical cocktail that Valencia will know how to make, and that should help you with your Ice-9 problem. I'm sorry I couldn't do better.

Impact in eighteen minutes. The missiles are slower than I thought they'd be. But the EMP will knock out any chance of my sending this message, so I'd better finish before they get here.

I'm going to take my bottle of bourbon and sit outside now. It's a fine day. The sky is very blue, very clear, and there's a slight breeze that will swirl the fallout around this whole valley. Not that it will matter after impact turns the sand to glass and every living creature on the surface dies.

When the blast comes, there's a chance it'll leave my silhouette in carbon on the wall. Some of me will be left behind even when I am gone. Isn't that a nice thought?

Through the heat haze you can see the mountains, and the military base there where they moved it in 1990. I wonder if there's anyone alive there. I hope not.

All right. I'm going now.

There are a few people who I hope are alive to read this, but I only have anything to say to one of them now.

Max.

I'm so sorry.

But if it had to perish twice,

I think I know enough of hate

To say that for destruction ice

Is also great

And would suffice.

notes:

The Cold War has always interested me, and while I wasn't raised during it, my childhood was colored by enough of its echoes that when I heard that the last Maximum Ride book actually did end the world, I knew what I had to do.

"Duck and Cover" is a short civil defense/propaganda film, first shown in 1952, which is aimed to teach children what to do in the event of nuclear attack. It famously features the character of Bert the Turtle.

From the 1950s into the 1980s, schools and towns in the United States drilled for nuclear attacks. There's an iconic photo of one, probably from a LIFE article, depicting children under their desks.

On The Beach is a 1957 novel by Nevil Shute about life in Australia just after nuclear war has destroyed the Northern Hemisphere, and fallout drifts south to kill the Southern Hemisphere. There's also a movie.

Alas, Babylon is a 1959 novel by Pat Frank about the aftermath of nuclear war on the little town of Fort Repose, Florida.

Fallout is a 1997 video game where you play as a character emerging from a giant fallout-shelter Vault after a nuclear apocalypse. The opening cinematic features "Maybe" by The Ink Spots.

The inter-section quotations are from, respectively, "Fire and Ice", Alas, Babylon, and "Maybe".

Astute readers will note that hey wait, Jeb was on the plane to that island in Nevermore. That wasn't dramatic enough for me, and I like Death Valley much better than the tropics as a setting anyway.

Also I didn't read that book, and could barely focus on the summary on Wikipedia long enough to pick out details to steal.