Hypnotherapist Dr Michael Strother has a dangerous gift: he gets flashes of the inside of his patient's minds. Whilst trying to help a detective stop smoking, he sees in her mind a young girl floating below the surface of a stream. He is soon caught up in the detective's pursuit of a serial killer. Although the girl has managed to escape from him, she has been struck mute by her trauma. Only Michael can get at the terrible images locked in her mind, and provide a clue as to the where abouts of the killer.