PROBE: The Zero Imperative

Former UNIT luminary Liz Shaw and her assistant Bayliss are investigating a series of bizarre murders, all committed near a soon-to-be-closed psychiatric hospital. When the hospital is unexpectedly reprieved by rich Industrialist Peter Russell events seem to move out of Liz's control. Are the incumbent director of the clinic, Doctor Dove and his predecessor Doctor O'Kane harboring the killer? What is the centuries-old horror hidden in the grounds? And what exactly is the secret of room zero?

• 
  Caroline John

  Dr. Elizabeth Shaw
• 
  Jon Pertwee

  Dr. Jeremiah O'Kane
• 
  Sylvester McCoy

  Dr. Colin Dove
• 
  Colin Baker

  Peter Russell
• 
  Mark Gatiss

  Dr. William Bruffin
• 
  Louise Jameson

  Patricia Haggard
• 
  Sophie Aldred

  Public Relations Officer
• 
  Linda Lusardi

  Louise Bayliss
• 
  Jonathan Rigby

  Cummings
• 
  Alexander Kirk

  Orderly