He looked wildly aound the empty playground, panic rising like bile in his throat. He'd heard stories -- didn't believe them, of course -- of people who slipped between the cracks in the city; disappeared, never to be seen again.
She was just playing some game, having him on. She'd be back any minute now, laughing at him for his fears.
"Very funny." His voice sounded loud, unnatural in the silence. Her black sweater, that she'd tied arund her waist, trailed from the rusty chain of the swing, dragging in the dust. A wind -- dry, warm, carrying with it a fetid whiff of decay -- swirled the dust around his feet, making the sweater flap like one of those birds he'd seen during their field trip to the Zoo. Ravens, he thought they were called.
Then he heard the sound. Faint, high-pitched, insistent, out on the very edge of hearing, he thought he'd imagined it at first. Then he thought it must be some malfunction in his iPod, but when he removed the buds from his ears he could still hear it. He turned his head this way and that, searching for the source. It seemed to come from the direction of an old road that curved off to his right between two ruined structures. Metallic, almost too high-pitched for human ears to hear, not mechanical in origin.
Organic, if he'd known the word.
The fine hairs rose on the backs of his arms as he stood silent, head to one side, listening.
Behind him, unseen, the swing recently vacated by the girl began to move back and forth of its own accord.