I’m standing on the steep slate roof of Allderdice High School, gripping a rain-spattered wrought iron decoration in one hand and holding up my other hand, palm out.

“Don’t,” I’m saying to the girl in front of me. “Please don’t.”

My hand wavers, tracing incantations of fear and panic in the air. Just beyond my outstretched fingers is something that has been spiraling out of control for years. Only I shouldn’t call her something. Should never call her a thing.

Somebody is what I mean.

It’s the technology, see? We can’t get away from it. Anywhere you find people, you find it. Clever little contraptions. Cunning strategies. We’re toolmakers born and bred; and even if you don’t believe in anything else, you’d better believe in that. Because that’s human nature.

It’s the tools that make us strong.

And it’s the tools that put a girl on the edge of this roof. I crawled out here against all advice the second I heard who it was. I owe this girl a debt and I can never repay it but I’m doing my best to try.

Samantha is just fifteen. The wind is smearing her brown hair against gray skies, pushing her tears in streaks across her blank, emotionless face. Allderdice is a massive school, built during the industrial genesis of Pittsburgh. Sam stands on the precipice, six stories up. The rain is spitting at us through afternoon sunlight, and the dull stone building seems to be bleeding or crying or both.

I can’t believe she’s really going to jump. Not after all she’s been through.

You make a tool to fix a problem, right? But—and I’ve thought about this—it’s the boundaries that define us. Bold, black lines that can’t be crossed—the limits of human ability. Lately, the edges have been torn off the map.

Now we’re all getting lost.

Eight years ago a little kid named Samantha Blex missed a week of class. In the first photos on the news, you could see Sam was a little cross-eyed. She smiled a lot through her kid-sized purple eyeglasses. Cute. The kid was all slobber and grubby fingers and grins. Had a habit of putting blocks in her mouth.

That’s why, when Samantha walked back into school after her weeklong hiatus, a lot of the other kids’ parents were scared. Terrified is more like it. A textbook case of fight or flight, with a serious lean toward fight.

See, Sam wasn’t cross-eyed when she came back to class. She didn’t put blocks in her mouth anymore, either. In fact, Samantha Blex pretty quickly demonstrated that she was now the smartest kid in third grade. After a few breathless rounds of testing, Sam turned out to be in the top-hundredth percentile on citywide intelligence tests.

The kid had one hell of a week away.

In an interview, Sam’s teacher told a reporter in a shaky voice that he wasn’t sure if Sam was still the same little girl, now that she’d visited her doctor and been given a Neural Autofocus implant. That quote grabbed a lot of airtime. I felt really bad about it later. Should have known better than to say it.

And that’s how it started. With sweet little Sam walking back into my classroom, looking me right in the eye with a new spark of intelligence—a new electricity altogether.

Where’d the spark come from? It’s simple enough. An aspirin-sized piece of conductive metal, an amp, carefully placed in the prefrontal cortex of the kid’s brain. A baby squid pulsing with an exquisitely timed series of electrical stimulations, gently pushing her mind toward the beta one wave state. Focused concentration, 24-7. This sharpened focus massively amplified her intelligence, bulldozing away the dim, mild, slobber-mouthed little girl I knew.

And only a little nub of dark plastic on her temple, like a mole, to show for it. A maintenance port.

Just like mine.

“I know how you feel, Sam,” I call to the coltish teen on the roof. “I get the stares. I hear the whispers. We can make it through this.”

I’m flawed hardware, like anybody. Have been for a long time. Epilepsy. My doctor says it’s a Tower of Babel in my head and I believe him. Of course, I would. My doctor is my father.

But the nub on my temple doesn’t lead to anything as hot shit as a General Biologics Neural Autofocus unit. It’s just a simple stimulator designed to treat epilepsy and keep me from swallowing the old tongue. Proverbially. Dad has always said that doesn’t really happen.

Still, turning my implant off is not an option. And that’s the bitch of it. These tools we love so much have burrowed under our skin like parasites. They’re in our brains now, our joints and organs. Crouching behind our eyeballs and clinging to our sinuses. Making us smarter and stronger and always, always more dependent.

“You don’t know how it feels,” says Sam. “You’re medical. Not elective. You’ve got no inkling.”

Sometime in the past, in some sterile office, a doctor said Sam had a problem. She had a little trouble concentrating, that’s all. But there was a solution available. And her parents chose to use it. They had a little bit of money and they wanted the best for their daughter and they were willing to take the risk. Any parent might have done the same.

“You didn’t choose this, Sam.”

“Tell me about it,” she mutters, eyeing the ground.

It was my first year teaching. Age twenty-two. Those chubby faces with their quick eyes sent me packing to teach high school the very next year. But I was there. I watched it all begin. Now, I’m crouching on the roof and inching away from the safety of the window and I’m watching it end.

“Stop that, Mr. Gray,” Samantha warns. She sounds slightly irritated, as if she’d caught me picking my nose. “Don’t come any fucking closer.”

I’m creeping across the spine of the building toward her now. A shivering, cowardly twenty-nine-year-old turtle on a slippery log. My knees and crotch and chest are blotched with water, my cheeks sprinkled with drops. Please, please, please, I’m thinking. Please don’t let me slip and fall and die this morning with my water-splotched crotch and my goddamn useless pencils in my shirt pocket and my soft clean hands with no calluses on them. This roof is slicker than ice. Slicker than a fucking waterslide and there’s no going back, so I hump it forward and ignore Sam’s annoyed voice.

She gives up protesting, and waits.

It was the Pure Human Citizen’s Council that pressured schools across the country into barring implanted kids. They said the few modified kids were taking precious resources away from the vast majority of human kids. It was true and Allderdice agreed, but Samantha’s parents were passionate and that’s how she ended up before the Supreme Court. A poster child for the inevitable future.

The lawyers picked Sam because she was a straight Neural Autofocus job. The nub on her temple wasn’t connected to the minnow’s flash of a retinal implant in her eye or a gleaming prosthetic limb. She was just a little girl, pretty and pure—save the one inhuman flaw buried inside, the truth of it flickering out into her IQ score.

Finally, my face crosses over into shadow. I see a knee-length skirt snapping in the breeze. Samantha stands with her hands on her hips, resigned.

I realize that she hasn’t jumped yet because she is trying to figure out how to make sure I am safe. A relieved breath hisses out of me, a whimper. We both hear it and think about it for a second.

“Jesus, you’re a pussy,” says Samantha. She glowers down at me like a ship’s figurehead sprouting from the peak of the roof. Too hard to be made of wood. Made of metal. Little flecks of it, anyway.

“I’m jumping,” she says. “Trust me, you’d have jumped years ago.”

“No, Samantha—”

“Shut your mouth,” she snaps. “You don’t know shit. I’m smarter than you, remember? You couldn’t teach me back then, so why try to talk to me now? Just shut up. I’m jumping. The impact is going to kill me instantly. It’ll take about two seconds to fall.”