# Chapter One: The Find

I was cutting through Riverside Park on my way back from class when I saw it. A glint of silver in the grass near the jogging path, half-buried where the groundskeeper's mower had obviously missed it.

It looked like a TV remote that had been designed by NASA. Matte silver, sleek, with a little screen on the top and two dials on the sides. No buttons, exactly. Just a recessed red switch where your thumb would rest.

"Lost your phone, dude?"

I looked up. A woman was jogging toward me, earbuds in, ponytail swinging. Mid-twenties, athletic build, pink tank top and shorts with matching sneakers. She slowed as she passed me.

"No, uh—" I held up the device. "Found this. Is it yours?"

She squinted at it, shaking sweat off her forehead. "Weird. Looks like one of those universal remote things. Someone's trash, probably." She shrugged. "You should toss it, whatever. Have a good one!"

She resumed her pace, and I should have let her go. Instead I looked down and noticed the screen had lit up. Two silhouettes appeared on it: one shaped like me, one shaped like her, with a dotted line connecting them. The distance between us, maybe fifteen feet, displayed as a number in the corner.

Underneath, in tiny blocky text: TARGETS ACQUIRED. HEAD SWAP READY. CONFIRM?

My first thought was that it was a prank. Some kind of AR toy. My second thought was that there was no way the screen knew about both of us unless it was doing something real.

I'm not proud of what I did next, but in my defense, I was a bored twenty-year-old engineering major with three unread textbooks in my bag. I thumbed the red switch.

The world popped. Like a flashbulb went off behind my eyes, silent and white. For half a second I felt like I was in two places at once.

Then I was fifteen feet away from where I'd been standing, and I was moving. Fast. Legs pumping, arms swinging, midfoot striking the pavement in a rhythm my legs apparently knew by heart even though my brain had never learned it.

I stumbled to a halt so hard I nearly ate the pavement. Looked down.

Pink tank top. Shorts. Sneakers that were somehow already tied. Slim, toned arms that did not belong to me, smooth tan skin, a …