This chapter is dedicated to Wild Rumpus, a store that is, all on its own, a reason to go to Minneapolis (there are other reasons to go to Minneapolis, but even if they went away, this one would do). They have a very nice chicken at Wild Rumpus, who wanders the countertop and greets the customers. You can buy her eggs. There are rats under the floor at Wild Rumpus, and you can see them through transparent panels (in the horror section, of course). And there are books. Great books. Lots of them. And nice places to sit and read them. Plus, very clever people to help you find the book you need to read next.

Wild Rumpus: 2720 West 43rd Street, Minneapolis, MN 55410, +1 612 920 5005

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I convinced Ange to let me go and get some water from the infirmary's big cooler -- "My butt's getting numb" -- and took the chance to survey the human wreckage. It was terrible, and I thought I knew what had caused it.

When I got back to Ange, I handed her my water bottle and watched her drink, then said, "Ange, if I told you something crazy, would you listen?"

She rolled her eyes. "Marcus Yallow, you've been telling me crazy things since the night I met you. Have I ever not listened?"

She had a point. "Sorry," I said. I leaned in close to her. "Back at the temple burn, do you remember a woman walking around with a camera, right in front?"

She shrugged. "Not really. Maybe?"

I swallowed. What I was about to say sounded crazy in my head, and it was going to sound crazier out in the air, and it was just for starters. "It was Carrie Johnstone," I said.

Ange looked puzzled for a moment, like she was trying to place the name.

"Wait, Carrie Johnstone? The Carrie Johnstone?"

I nodded. "I got a couple of good looks at her. I'm sure." I didn't sound sure. "I'm pretty sure."

"So she's a burner now? That's weird."

"I don't think she's a burner, Ange. I think she was here to kidnap Masha and Zeb."

"Uh-huh," Ange said. "Marcus --"

"Dammit," I said, "you said you'd listen!"

She shut her mouth, opened it, shut it. "I did. Sorry. Go on."

So I told her about what I'd seen, Zeb and Masha and the goons, and my stupid, half-baked attempt to catch them as they'd marched into the night.

"So what are you saying?"

"What do you think I'm saying, Ange?"

"It sounds like you think that Johnstone and her pals kidnapped Masha and Zeb."

I didn't say anything. Of course that's what I was thinking, but that was just for starters. I had another idea, one that was even more crazy-sounding. I wanted to know -- had to know -- whether it would occur to Ange, too, or whether I'd just had my brains rattled when I face-planted into the gypsum flats of Black Rock Desert.

"What?" she said. Then she opened her eyes a little wider. "You think that Johnstone blew up Octotank to -- what, to cover her getaway?"

I closed my eyes. I couldn't bear to look at Ange, because she was staring at me like I was nuts.

"Look at it this way: they've been driving fire-breathing art cars around the desert for decades now, without a single major mishap. The first time one goes boom, it happens just as Carrie Johnstone, a war criminal with a history of ruthless disregard for human life, is in the middle of kidnapping a rogue agent who has been trafficking in giant troves of secret documents. The timing of the explosion is perfect, and a hundred percent of the attention on the playa is occupied for the next several hours. Meanwhile, they could get away in a million ways -- hell, they could just stroll over to the trash fence and hop over it and leg it out over the mountains, or jump into a waiting car. The Black Rock Rangers will all be scrambling to help the wounded, not patrolling with night-scopes for people trying to sneak in without a ticket."

"Yeah," Ange said. "I suppose." She squeezed my hand again. "Or: people have been driving home-made flamethrowermobiles around the desert for decades, and it was only a matter of time until one blew up. And you saw someone, in the dark, do something that looked like a kidnapping, but at a distance, and right before you had your head knocked around and broke your nose, after a week's worth of sleep deprivation, recreational chemical use, and caffeine abuse." She said it calmly and evenly, and kept hold of my hand as I struggled to go.

"Marcus," she said, grabbing my chin and forcing me to look into her eyes. I winced as she put pressure on the sutures in my lip, but she didn't loosen her grip. "Marcus, I know what you've been through. I went through it too, some of it, at least. I know that improbable things happen sometimes. I was there when Masha gave you her key. You have the right to believe what you believe."

"But," I said. I could hear there was a but coming.

"Occam's Razor," she said.

Occam's Razor: the rule that says that when you're confronted with a lot of explanations for a given phenomenon, the least complicated one is the one that is most likely to be right. Maybe your parents won't let you into the locked drawer in their bedroom because they're secret spies and they don't want you finding their cyanide capsules and blowdart rigs. Or maybe that's just where they keep their (eww) sex toys. Given that you know that your parents have had sex at least once, and given that (in San Francisco, at least) odds are good they've bought the odd dildo or two over the years, the super-spy hypothesis has to be shuffled to the bottom of the pile. Or, to put it another way, "Extraordinary claims require extraordinary evidence."

"I like Occam's Razor," I said. "It's a useful thinking tool. But it's not a law. Sometimes, the unlikely happens. It's happened to both of us. I saw what I saw, and I saw it just a few days after I saw Masha, who is mixed up in all kinds of espionage stuff, and who was acting paranoid as hell. Maybe she had a good reason for that."

"Yeah. And maybe all that stuff primed you to interpret anything that happened in the days that followed in dramatic and scary ways." She let go of me and looked away at the crowds of people. "Marcus, if you think you know what happened, you know what you should do. Masha told you what to do."

If you ever hear that I've gone down, or Zeb's gone down, release it. Shout it from the mountaintops.

You know what? I hadn't even thought of that. I'd been so fixated on rescuing Masha, or proving I wasn't losing my mind, I'd totally forgotten that I was her insurance policy, that she'd fully expected that she might "go down" and that she'd entrusted me with her personal countermeasure.

Now that I thought of it, I found that the idea terrified me.

"I don't know what's in her insurance file," I said, "but I've got an idea that if we were to make it public, it'd make some very powerful people very angry at us." I flashed on how I'd felt when Johnstone had been standing right over me, that paralyzing horror that started somewhere at the bottom of my spine and froze me to the spot. I believed that Johnstone had kidnapped Masha to keep the contents of that file a secret. What would she do to me if I released it?

Worse: what would she do if Masha told her I had the insurance file?

"Oh, crap," I said. "Oh, Ange, what'll we do?"

We both agreed that we didn't have to do anything that night. I was injured, we were in the middle of the playa without functional laptops, and, to be honest, we were both scared witless about the insurance file and what might happen if we were to go public with it. I still had the USB stick with me -- I'd kept it in my utility belt, in its little secure zip-up money-belt section. I kept compulsively checking it until Ange made me stop. After a few hours, we decided that I didn't have a concussion and snuck away before anyone could disagree with us. We caught a few precious hours' sleep in the tent, holding tight to each another, before the alarm on Ange's cheap, rugged plastic watch went off, weep-weep-weep, and we got up to break camp and start Exodus.

We'd slept in our clothes -- it got cold at night in the desert, even with our sleeping bags zipped together for shared warmth -- and when we got outside the tent and stood, I saw that my burnoose and the front of my T-shirt were crusted with dried blood from my broken nose and swollen lip. My nose and lip felt like they'd ballooned to elephantine proportions in the night, though when I brushed the dust off a nearby car's side mirror and checked my reflection, I saw that they were merely double their normal size. I looked like I'd been run over by a tank, one of my eyes blackened, my mouth distorted in a weird, pouty sneer, my taped-up nose misshapen and bulbous.

"Groagh," I said, and my lip split again and began to seep blood. My face hurt. They'd given me some Tylenol 3s at the infirmary and I took two of them, washing them down with cold-brew, undiluted straight from the mason jar, then kept on swigging at the bean juice. I needed energy if I was going to help Ange break down our camp and lug our gear across Black Rock City to the camp where the guy who was giving us our ride had been staying.

Ange said, "You just sit down, Marcus, I got this."

I shook my head and said, "Nogh," a painful syllable that made my face bleed some more.

"Forget it, sit down."

I shook my head again.

"God, you're stubborn," she said. "Fine, kill yourself. Don't come running to me when you're dead."

I waved at her and handed her the cold-brew jar. She made a face. "There's blood in that one." I looked at the rim and saw it was smeared with red from my lip. I dug another jar out of the ice chest and passed it to her. She went to work on it. "Got to drink plenty of water, too," she said. "Remember, this stuff is a diuretic."

She was right. I alternated two swigs of water for every swig of cold-brew at regular intervals over the next forty-five minutes, as I crammed, jammed, piled and mashed our stuff into our bags. The biggest item to pack, by far, was Secret Project X-1 and all its assorted bits and pieces.

When I joined Noisebridge, I hadn't really known what I wanted to do. All I knew was that these maker-types had set up a hackerspace in the Mission, filled it with lathes and laser-cutters and workbenches and drill presses, and that anyone could join and use the gear to make, well, anything. I'd hung around for a month or two, dropping by after classes to just sit on the sofa and see what people were up to, bringing along my laptop and school-books and studying in between watching as my fellow Noisebridgers invented every mad and amazing thing under the sun.

Noisebridge was a fantastic place. It had its own space program. Seriously. Almost every month, they launched homebrew weather-balloons crammed with cameras and instrument packages to heights of seventy thousand feet and more and retrieved them. There were people hacking robots, cars, clocks, pet doors, toys, and rollerblades -- not to mention video-game consoles, server hardware, autonomous flying drones, and so on and so on.

And they had 3D printers, devices that could produce actual physical objects on demand, based on 3D files they made or downloaded from the net. Most of these had started off life as MakerBots, an amazing and popular open source 3D printer kit that you assembled yourself. MakerBots printed in plastic, using spools of cheap plastic wire, and the results were pretty amazing, especially considering that the kits cost less than a thousand dollars, and you could make one for less if you scrounged around for the parts in surplus catalogs and the prodigious bins of spare electronics at Noisebridge.

Being open source, MakerBots were a hacker's paradise, and people all over the world had modified their printers to do extraordinary and amazing things. The big excitement when I joined Noisebridge was a successful conversion to laser-based powder printing, which involved using an apparatus to spread a thin layer of plastic powder on the printing surface, then melting it into specific forms with a laser, then adding another layer of powder and melting it again with the laser, over and over, until you'd built up the whole solid shape.

Powder-based printers cost a lot more than MakerBots -- like $500,000 or more -- and they were all locked up in a complicated set of patents that meant that only a few companies could make and sell them. But patents didn't stop people from modding their MakerBots to do powder, and once they started, it became the most popular form of MakerBot modding in the world. Naturally it was: the objects that came out of a powder printer were much smoother and more detailed than the stuff that came out of a plastic wire printer, and with a powerful enough laser, you could use metallic powders and produce precisely made objects in stainless steel, brass, silver -- whatever you wanted.

But what interested me wasn't printing in steel: it was printing in sand. There were lots of people around the world who were experimenting with alternatives to plastic or metal powder as a printing medium, because, well, anything you could melt with a laser could be fed into a printer. You could print the most wonderful stuff with sugar or make brittle, tragically short-lived stuff out of the whey powder they sold in bulk for body-building. But like I say, sand was the stuff that caught my imagination. When you melt sand, you get glass, and a beautiful, streaky kind of glass it was, and every day brought more amazing sculptures and jewelry and action figures and, well, everything made of melted sand. As a printing material, sand was as cheap as it got, cheaper even than whey powder.

But there wasn't any sand on the playa. What we had instead was dust. Gypsum dust, the stuff that they make drywall out of. In other words, stuff that you could (theoretically) make some wicked structures out of.

That was my plan, anyway. I made my own MakerBot, downloading the plans from their site, lasercutting the balsa wood, building the Arduino-based controller, scrounging parts when I could, buying them when I absolutely couldn't find them, but only through surplus stores. In the end, it cost me less than $200, and took me about two months, and it worked beautifully. As soon as I got it working, I promptly broke it (of course) and tried to get it running as a powder printer. That was a lot more complicated, and the powerful laser it required cost as much as the rest of the printer. But I got it working, too.

And while I was gutting through that breakdown/upgrade/fix cycle, I hated every minute of it, felt like the world's biggest idiot for not being able to do something that everyone else (for some extremely specialized definition of "everyone else") seemed able to pull off. But you know what? I couldn't stop. Because whenever something went wrong, it always seemed like the solution was tantalizingly within reach, and if I just did one more thing I'd have it all working. One more thing and one more thing and one more thing again, and then, miraculously, it worked! I went from nearly comatose to elated beyond all reason in one millionth of a second, as the air above my workbench was filled with the sweet, toxic smell of melting sand and a bead of glass formed on the build platform. The bead took form, and my calibration testfile, a block with several holes in it that were sized to snugly fit a collection of standard bolts I kept in my pocket for testing, began to take shape.

I didn't need to use them. I could see that it was working. I'd taken that stupid printer apart and put it back together hundreds of times. I knew its movements like the movements of my own hands and its sounds like I knew the sound of my own heart. I laughed and danced on the spot, for real, and watched it go through its paces for a few minutes, before the excitement got to me and I raced out onto Mission Street, ready to grab the first person I could lay hands on and drag them back to Noisebridge to see my machine working! Of course, as soon as I got out the door, I realized it was three in the morning, and there was no one to be seen.

So that was my MakerBot, and the plan had been -- what else -- to mod it to print in playa dust, using melted sugar as a fuser. Sugar's strong -- melt some caramels and brush them onto a 2 x 4 and clamp another 2 x 4 to the spot overnight while the "glue" sets and you'll get a joint that's so strong the wood will tear apart before the glue gives. But sugar is also water-soluble, so when I was done, my playa-dust prints could be dissolved in water. "Leave no trace," just like Burning Man principle eight says. I did some test runs, using powdered drywall that I ground up in an old hand-cranked coffee grinder, and I had it working pretty well when I disassembled the MakerBot and packed it up to take to the playa.

That was Secret Project X-1, and I swear it worked like a charm when I left San Francisco. I have no idea why it failed so miserably when we got to Black Rock City. The solar panels tested out good, and I borrowed a multimeter from another camp and checked every circuit and contact, and everything seemed to be in working order. But the stubborn, evil bastard refused to even turn on.

Even bloodied and bruised and traumatized and terrorized, I still felt a pang when I packed away X-1 again. I had this incredible plan to 3D print the most amazing shapes and objects out of playa dust -- fanciful animals, busts of famous monsters, all the best junk from Thingiverse, the online library of free 3D forms. I was going to be the best, coolest, cleverest burner in the history of the playa. A legend. Instead, I was the guy who sweated and swore at his invention for 24 hours straight before his girlfriend went upside his head and told him to stop swearing at his printer and get out there and enjoy Burning Man. She was totally right, and everyone liked my cold-brew, but man, it hurt to pack away X-1 without having printed a single widget.

"You'll get it working next year," Ange said. "Don't worry." She looked off at the cloud of dust rising from the playa as Fifty thousand burners packed up and got ready to turn Black Rock City back into Black Rock Desert (though there'd be cleanup teams staying behind for a few months going over the whole desert, erasing the final signs of human occupation). "We have to go."