I’m about to give up and start running when I notice tiny numbers imprinted on the postcard, so small they almost fade into the background. I hold the card up to the sky, tilting it toward the morning sun until I can make some of them out: page numbers.

My sister made a key.

Trying to keep my breath steady, I turn to the corresponding pages in the book that held the postcard. I scour the history of three buildings and want to scream in frustration when something catches my attention.

A diagram of the subway. A picture of a rusted-out sign over an old metal door. An arrow pointing to the green-roofed building that’s just down the street from me. A footnote about a ghost station in the basement.

I tuck the postcard into my shirt and start running across the roof to the next building and then the next, vaulting the short walls in between. I might be a fool for believing what the book says. It’s my sister who believes parts of this city have truly survived since the Return—that there are still places rooted in the before time.

But it’s a chance I have to take. If I stay up here the Recruiters will eventually catch up to me, overpower me. Take me back to the Sanctuary, where Catcher and I will be trapped forever.

I can’t do that to him. I’d rather risk myself than see him turned back into their lackey.

The morning wind gathers around me, pushing balloons lazily across the sky high over my head. All of them chasing a strip of smoke on the horizon leading to Catcher and safety. All of them so close but beyond my grasp.

Under my feet the bridge jostles and jumps as I cross, one of the boards splitting when I land on it, my leg breaking through. I grapple with the rope railings, twisting my wrist through one to stop my fall.

My breath comes in jerks and I close my eyes for just a moment, the muscles of my arm straining to hold me up. Slowly I ease my way onto the next board, testing its strength before transferring my weight.

Already I can hear the Recruiters shouting behind me, closing the distance. My body begs to run, but I force myself to take even steps, testing each section of the bridge before moving across it, agonizingly slow.

I can’t stop glancing over my shoulder, watching the uniform-clad bodies weave their way nearer and nearer. Unable to keep the need to run from taking over, I leap from the end of the bridge onto the roof of the green-roofed building, my feet slipping on a patch of ice when I land.