All of Coop's senses were on high alert, and so he heard the whisper at once. His ears picked out the faint sound of her voice, instantly determining the direction from which it came.
He moved quietly and carefully, in part because of the whisper and in part because of the very, very bad feeling he had in his gut about this. There was something...wrong.
"Where are you?" he returned in his own whisper, his voice carrying a little better than he liked in the empty store.