THE PHYSICIAN and Peri end up in the Museum of Aural Antiquities, where every sound is stored for posterity – from your speeches of Visteen Krane to security service wire taps and interrogation tapes. But they also find an intruder, mysteriously transformed recordings, and a lifeless body. In a short time the Doctor realises that there surely is more going on than a basic break-in or murder. How do he defeat a creature that’s made of genuine sound?