The Second Echo

Ivy had one hour to finish the new concert hall's sound test before the mayor arrived. She stood alone at center stage, clapped once, and listened as the echo faded beneath the balconies. Clean. Even. Exactly what the builders had paid for. Her second clap came back twice. Ivy checked the empty seats, then called, "Is someone in here?" The hall returned her question in her own voice. A moment later, from somewhere above the ceiling, her voice added, "Do not let them open the doors."