"Two reasons for that," Myoko answered. "First, the nanites superficially resemble conventional microbes. Elementary camouflage. Second, the nanites are smart… at least some of them are. Some are like brain cells, coordinating other nano activity. If the brainy ones notice a biologist getting out a microscope, they tell their fellow nanites to clear out. If worse comes to worst, they send in nano-stormtroopers to crack the microscope lens."

"Nanites are strong enough to do that?"

Myoko put her hand on my arm. "Phil, they're strong enough to lift Impervia. That's how it works. My psionic powers are just a hotline to the local brain-nano. The brains summon other nano from the surrounding environment to act as microscopic sky-cranes… and up Impervia goes."

I tried to picture the physics of how that would work. If lifting Impervia was the action, where was the equal and opposite reaction? I couldn't figure it out and didn't want to display my ignorance, so I changed the subject. "So how did you get this psionic hotline?"

"There are nanites everywhere, Phil-in the food we eat, the water we drink, the air we breathe. They get inside us, the same way normal microbes do. Our lungs, our bloodstreams, everywhere. Some drift inside by accident; others deliberately target humans and work into specific areas of their bodies. Particularly into the wombs of pregnant women."

"That doesn't sound healthy."

"Consider it a mixed blessing," Myoko said. "Some types of nano-and there are thousands of different breeds, each designed to perform a specific function-some types target the brains of developing embryos. They embed themselves shortly after conception so they're incorporated into the child's gray matter."

I winced. "How many children are infected like that?"

"All of them, Phil. Every last child bom on Earth for the past four centuries. Animals too-the nanites are everywhere, absolutely inescapable. You have them riddling every part of your brain; so do I; so does everybody."

For a moment, I thought I was going to throw up. "What are the damned things doing in there?"

"Mostly waiting. For instructions."

"From whom?"

"Psychics and sorcerers." She gave me a pallid smile. "Even I don't like to contemplate that fact too long. But how do you think telepaths read minds? It's not tricky once you realize everyone's brain is full of nanites that have been linked into your mental processes almost since conception. They know what you're thinking… and they transmit it to receivers in the telepath's brain. As simple as OldTech radio."

"Simple." I made a face. None of this was the least bit simple. Were all the nanites in my head taking up space that should have been used by brain cells? Did they actually replace brain cells, the same way they'd replaced thirty percent of the natural bacteria and viruses in our biosphere? Were all my thoughts partly running on alien-built nanites rather than regular neurons?

And how did they get enough energy to transmit radio waves? Only one way: they must tap into the body's energy, sucking nutrition from blood just like normal cells. Parasites. Extraterrestrial parasites in the brain. Though I'd lived with them all my life, I still felt close to vomiting. "If we all have these things in our heads," I asked, "why aren't we all psychics?"

"Ah," said Myoko, "there's the trick. The nanites most people have in their brains lie dormant till they receive an outside stimulus… but as I said, there are different types of nano. One particular type-extremely rare-also plants itself into people's brains; but this type has the ability to initiate action. For example, it can tell the nanites in other people's brains to send it signals."

"And that's the difference between a telepath and everyone else? The telepath has one of these initiator nanites?"

"That's it. That's the whole secret." She gave a self-conscious laugh. "Of course, there are plenty of complications." Myoko lifted her gaze to meet my eyes. "Do you know what it feels like when I use my telekinesis?"

I shrugged. "I don't know… maybe like you've got a phantom arm?"

"An arm? Hell, I'd kill for an arm." She rolled her eyes. "You know what I've got, Phil? A phantom knee. My right knee, to be exact. When I picked up Impervia tonight, I visualized tucking my knee under her, then shoving her up, up, up… the feel of it, which muscles would move when, picturing everything exactly. Of course, I couldn't lift Impervia with my real knee-I can't keep a full-grown woman perfectly balanced with just my kneecap jammed against her back. My psychic knee can do things my physical knee could never pull off. But in the end, it's still just a knee; exasperatingly limited. When I think what I could do if I had a hand: the joys of manual dexterity, Phil, the joys of manual dexterity!"

I had to laugh. Myoko did too. "The thing is," she said, "it all depends where the initiator nanite plants itself in a psychic's brain… and how far outward it sends its pseudo-neural connections. My initiator landed in the part of my brain that controls my right knee. As simple as that. So when I focus my attention on my knee in a particular way, the initiator responds."

"Hum." I thought for a moment. "And it responds by sending radio messages to nearby nanites in the air. It tells those nanites to get together and lift Impervia… or to do whatever else the initiator wants."

"Exactly!" Myoko gave my arm a squeeze. "A psychic's power is entirely determined by where the initiator settles in. If it lodges in your visual cortex, you'll be able to see psionically. Maybe you'll be clairvoyant: your initiator can link with nanites half a continent away and see what they see. Or maybe you'll perceive auras… which means your initiator communicates with nanites in other people and presents their emotional states as colors. You might even be able to project optical illusions; your initiator sends images from your visual imagination to receiving nanites in other people's brains. Voilà: they see what you want them to see. There are lots of variations-visual processing occupies great swaths of our brains, and you get different effects depending on where the initiator lands within those swaths."

"I suppose if the initiator lands in a hearing center, you can hear things happening far away… or project sound illusions, or maybe hear other people's thoughts, transmitted by their own mental nanites."

Myoko nodded. "That's the idea. Things get weird if the initiator plunks down in an exotic corner of your mind; there was one guy at school whose initiator lived in his primary pleasure center and he could transmit the most…" She suddenly stopped in embarrassment. "Figure it out yourself."

"Lucky guy," I said.

"No," she replied, "very unlucky. He disappeared one day when he left school grounds. Now he's probably chained in some brothel where he has to make sure the paying guests have a good time… or he's playing gigolo to someone like Elizabeth Tzekich, who'll beat him if he doesn't give her orgasms on demand."

Myoko's voice had suddenly filled with bitterness… and her hand on my arm was an eagle's claw, fingernails digging fiercely through my sleeve. "Come on…" I began; but she gave me a look that made me hold my tongue.

"Don't try to comfort me, Phil. If you do, I might ram you through the wall. It's…" Her voice trailed off for a moment. "The threat hangs over every psychic's head. Always. Forever. The only protection is being too weak to interest the sharks. In a lot of psychics, the initiator attaches itself only loosely to the brain. You get a small intermittent power that isn't much use… or a power that takes a lot of strength and effort to activate. People like that-like me-are usually safe: more trouble than they're worth. But if you have a good strong power…"