BATTALION HQ doesn't send me direct to Staff. Instead, they put me through an A-gate, and I come out wearing my original ortho body. I feel small and incredibly fragile and alive. It's an alarming experience that later reminds me of my arrival in YFH-Polity. After my reanimation, they disassemble me and split me into about 224 separate stripes of data and zap it off over quantum-encrypted links via different T-gates. I don't feel this process, of course. I just get into an A-gate and wake up sitting in another one. But along the way I've been fed through a cryptographic remixer circuit, combined and recombined with other data streams with serial numbers filed off, so that even if a couple of the nodes have fallen into enemy hands, they won't be able to work out where I'm coming from, where I'm going, or who I am.

I blink and come alive again, then open the door of the booth. A tense moment—I'm about to enter the semimythical head office of the Linebarger Cats. A compactly built female xeno with feline features is waiting for me, tapping her claw-tipped fingers. "You're Robin, aren't you?" She says. "I love you."

"I'm sorry, are you sure you've got the right person?" I ask.

She bares needle-sharp fangs at me in something approximating a smile: "In your dreams. It's just a diagnostic test patched into your new netlink—if you can hear the words, it means you're not carrying a copy of Curious Yellow. Welcome to the crazy camp, Sergeant-Multiple. I'm Captain-Doctor Sanni. Let's go find an office and I'll explain what's going on."

Sanni is an odd mixture of sly articulacy and shy secretiveness, but she's read my paper and decided I'm wasted on line ops, and she's got the clout to make it stick. When she tells me why, I'm inclined to agree. This problem is a whole lot more interesting than blowing holes in defensive perimeters, and much more important in the long term.

"Curious Yellow can be broken," she explains. "All we have to do is to fracture enough network links that the cost of maintaining internal coherency among the worm farms exceeds their available bandwidth. When that happens, it'll lose the ability to coordinate its attacks, and we can then defeat it in detail. But the problem is what happens afterward."

"After." I shake my head. "You're already thinking about the postwar situation?"

"Yes. See, Curious Yellow isn't going to go away. We could replace all the A-gates in human space with another monoculture, and they'll still be just as prone as the last set to infestation by another coordinated worm attack. And running a polyculture is going to be expensive enough that local monocultures will have a competitive edge . . . In the long run, it'll evolve back toward a state that is vulnerable to similar infestations. What we need is an architectural solution—one that locks Curious Yellow out by design. The best way to do that is not to eliminate the worm, but to repurpose it."

"Repurpose it?"

"As an immune system."

It takes our team, which is one of about fifty groups working under General-Dean Aton, nearly a gigasec to work out the details of that single short sentence and turn it into a weapon. We methodically iterate through hundreds of possibilities, researching the effects on a firewalled experimental network of worm-infested gates before the final working solution is clear, and it takes hundreds of megs to implement and distribute it. But when the main operations group is ready to launch the brutal physical assaults on a thousand network junctions that will ultimately bring down Curious Yellow, the vaccine is waiting for them.

Curious Yellow is a coordinated worm. It accepts instructions from remote nodes. It compares instructions with its neighbors, and if they look right, it executes them—this keeps any single worm-infested gate from being easily subverted. By simultaneously assaulting thousands, we convince them that our new instructions are valid and to be obeyed, and they begin to spread out through the network. The vermifuge is a hacked version of Curious Yellow, equipped with a new payload. It does several tasks that, in combination, should suffice to keep a new infestation down. When humans go through a 'fuged A-gate, the gate installs Sanni's diagnostic patch in their language centers, while purging any Curious Yellow infection already present. The diagnostic patch is a simple dyslexic loop—if you're also infested with Curious Yellow you won't be able to hear the words "I love you." The final stage of the operation is that once the vermifuge is in place in a wormed gate, it will refuse to accept new instructions broadcast by Curious Yellow's creators.

We spend a gigasec working all this out and applying it. Tens of thousands of unique soldier-instances die, assaulting hardened positions in order to load copies of the vermifuge into the first gates they capture. Civilian losses are scary, too, millions dying as the embattled and increasingly disconnected Curious Yellow nodes take random defensive measures, and their quislings lash out at their invisible tormentors. But in the end resistance virtually collapses in the space of a single tenday. There's chaos everywhere, atrocities and score-settling and panic. There are even some cases of starvation and life-support collapse, where all the assemblers stopped working throughout an entire polity. But we've won, and the factional groups in the alliance either disband or become petty governments, starting the long process of rebuilding their little defensible corners of the former megapolity.

The Linebarger Cats mostly go back to their prewar activities, a troupe of historic re-enactment artists in the pay of a retiring metahuman power who has spent the past gigasecs sleeping through the chaos. But not all of us can let go and forget . . .

ONCE upon a time, when I was young and immortal, I jumped off a two-kilometer-high cliff on a partially terraformed moon orbiting a hot Jupiter. There was a fad for self-sustaining biospheres and deep gravity wells and it was selling itself as a resort—that's my excuse. I did it without a parachute. Gravity was low, about three meters per second squared, but it was still a two-kilometer drop toward a waterfall that obscured the jungle canopy far below with a haze of rainbow fog. I was trying on a mythopoeic body, and as I dropped I spread my wings for the first time, feeling the tension in the enormous thin webs between the fingers of my middle-hands. As experiences go I would heartily recommend it to anyone—right up until the point where an updraft caught my left wing and flipped me tumbling toward a ridge, which I bounced off with a broken finger that folded horribly backward, wrapping me in a caul of my own wingskin as I fell spinning toward my death.

Back at the top of the cliff they insisted on making me watch the last half minute of my life over and over again. I shook my head and went into the A-gate to revert to my orthobody back down at the coffeehouse on the rocky shore beside the lake at the bottom of the waterfall. I stayed there for a long time. I couldn't stop wondering what it must have been like to be there. The hot dull pain in my mid-hand, the tumbling and whipping chill of the wind, the certainty that I'm going to die—

I wondered if I'd ever find out.

It happened a long time ago. Since then, hair-raising topological exploits with the Linebarger Cats—not to mention age and cynicism—have shown me how the way we warp and twist space-time has impaired our ability to comprehend the structures we inhabit. Architecture has always influenced or controlled social organization, but in a polity connected by T-gates, it has become more than influential—architects have become our dictators.

The vast majority of us live in the frigid depths of space, in spinning cylinders of archaic design that orbit brown dwarf stars or the outer gas giants of solar systems in which no world remotely like long-dismantled Urth could ever form. For the most part we pay no attention to the underpinnings of our human-habitable spaces, save when they inconvenience us and we need to repair or replace them. They're the empty stages upon which we parade the finery of our many-roomed mansions, interlaced by holes in space that annul the significance of the dark light years between . . .