From the speakers again: "Thud. Thud. THUD." It was faster now.
Leo froze. The whisper wasn't from outside. It was from the page . He looked down at his hands. They were shaking. But it wasn't fear—it was curiosity. He typed a question into a blank space at the bottom of the PDF: "Who is whispering?" From the speakers again: "Thud
He hit enter.