The Secret Service Episode 9 The Deadly Whisper Episode Title: The Deadly Whisper Episode Description: Professor Soames has invented an ultrasonic vibrational rifle capable of destroying armoured vehicles. Plotting to use the weapon to shoot down an experimental aircraft, criminal Mark Slater and his gang kidnap Soames' daughter, Anne. With the professor's help, Unwin and Matthew rescue Anne and then set out to foil Slater.