This time it's another fair-haired, soft-voiced young person. However, despite ostensibly being a twelve year old girl, this is potentially the most menacing person Morgan Waller has ever encountered – and she met O5-11 less than a week ago. There's just something about her eyes that makes Morgan feel like running is futile. She's wearing a stained white smock over a cornflower blue dress, and is accompanied by a floating humanoid figure in a shapeless hospital gown.

"Hello, Miss Davis."

"Hiya Herbie! Good to see you again. Nice to meet you too, lady."

"My pleasure."

"Hey, meatbag! Bonesaw has arrived."

She pulls a crumpled piece of paper out of her front pocket and flicks it at the attendant.

It bounces off her face and lands on the table. She doesn't even blink.

"Which institution is your doctorate from?"

"Do I look like Doogie Howser to you? Don't answer that question."

"Room 303, Bonesaw. The opening ceremony begins in nine minutes."

"Gotcha. Right, lady, let's say you're working on a brain and all the information you care about is stored in the central nervous system – that's reductive neurology. Herbie knows all about that stuff. But then, let's say you're doing exploratory neurosurgery because you want to get at something intangible. Lotsa folks keep their selves outside themselves, and there's some other nifty stuff out there you can't pin down inside a cranium with your forceps, you know? That's more on the holistic end."

"So goes the theory," West says bitterly.

Are they just discussing anomalies now? While there's an anomalous bald girl, floating right there? Apparently so. Neither of them are acting like this is weird, so neither will she. Time to earn some brownie points.

"A lot of psychic phenomena are higher-dimensional by nature. That's how they do the seemingly impossible. If you aim a laser at the moon and flick it from one side to the other, the illumination will travel faster than the speed of light. A perspective embedded in that surface would see something they couldn't explain in the framework of special relativity. The idea generalizes to three dimensions."

"I understand the principle of it – I read Flatland as a child, it was surprisingly didactic and entertaining for a story about talking polygons – but what's always evaded me is the reason. Why would higher-dimensional phenomena pass through the Earth as chill winds and apparitions of the dead?"

… he's got a point there.

Bonesaw holds up two fingers. "Two types of paranormal activity. First, the artificial. Watches have watchmakers. Second, the natural. Brains kinda look like floppy watches if you squint at 'em, but they happened in a stones-rolling-down-a-hill sort of way. I've been studying the shape of that hill, trying to see what makes psychic clocks tick – that's why I brought Gemini."

She pats the floating girl's leg. She drifts with the force of it in a mechanical way, like an ice cube sliding across a flat surface, but otherwise still looks like she's been snowed with midazolam.

"You induced voluntary levitation in a human subject?" Morgan blurts out.

"Psh! Nah, she could do that already. There's a giant thingy standing about a foot away from us along the W-axis holding her up – I call 'em passengers, 'cause they just mooch around in the temporal lobe without paying rent. Anyhow, her mind was already sensitive so I figured she'd make a good pilot study for testing how mental powers develop. Here, I'll give you a sneak peek for my talk later."

She grabs the hem of the hospital gown and yanks it aside.

Beneath the gown, the floating girl's body is depilated but otherwise ordinary – apart from the torso. The skin and fascia are split apart from throat to groin, and in its place are what looks like the head and shoulders of a completely different person. A fragment of a teenage boy occupies the entire body cavity in place of her organs. His head is affixed to where the girl's sternum ought to be, and a single arm protrudes from her belly like a grotesque umbilical cord. The empty space to either side of his face in her thoracic cavity is sealed with a transparent membrane, showing off a network of shielded cables and blinking lights threaded between the remains of her pectoral muscles. The rest has been artfully stitched closed, concealing whatever interventions are currently keeping them alive.

Neither of them have even the slightest alertness about them. The boy's arm sways limply in the breeze, no longer trapped by the hospital gown.

He leans in to inspect the joinery. "Impeccable work, Miss Davis."

Bonesaw kicks the ground bashfully. "Aww, shucks. They're siblings, I didn't even have to muck around much to get them histocompatible."

"Reminds me of that guy from the end of Total Recall," Morgan says. She waves her hand in front of the boy's face and gets no response. Their facial features are very similar – not counting the baldness, Morgan suspects that part isn't genetic.

"I was wandering through a destroyed town and found him like this," she explains. "Went back to his sister, told her I could save him, and Bob's your uncle! I figure, hey, do I really want to wait until conjoined twins fall into my lap, or do I wanna seize the initiative myself? Plus, they both had passengers already – weird things happen when twins get passengers. I didn't want to confound my experiment like that."

"What are your observations thus far?"

"I'm not sure," Bonesaw confesses. "I was hopin' for spontaneous telepathy, but that turned out to be a bust. Maybe they're off having accurate visions of the future where I can't see; I'm not a mind-reader."

Gemini technically had a second trigger event on the operating table, but Bonesaw has caused enough of those by now that it was less of an exciting learning opportunity and more of an unwanted complication during a fairly delicate surgery. Admittedly it was an unwanted complication involving lasers and hallucinatory aliens, which are the most awesome kind, but telepathy it was not.

This is a travesty. She's doing it all wrong!

"The important part is the mental link – once you have enough spare gray matter to work with, it has to be able to pass information around freely. What you need isn't just conjoined twins, you need craniopagus twins. Regular twins work too, if they already have a mental connection, and some non-twin people who have the right phenotype if you figure out how to screen for it. Then you do your active induction, whichever kind you're using."

That might explain why Case 70s are the way they are. If the passengers are using the corona pollentia in both twins and need to physically bridge them, one way to do that noninvasively is moving the twins on top of each other in the fourth dimension and running the bridge through the void.

"Huh. And what kinds of active induction are we talking about, traumatic events?" That would be convenient – Bonesaw is very, very familiar with trigger events.