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
as Dr. Elizabeth Shaw
Jon Pertwee
as Dr. Jeremiah O'Kane
Sylvester McCoy
as Dr. Colin Dove
Colin Baker
as Peter Russell
Mark Gatiss
as Dr. William Bruffin
Louise Jameson
as Patricia Haggard
Sophie Aldred
as Public Relations Officer
Linda Lusardi
as Louise Bayliss
David Terence
as Daniel O'Kane / Eustace O'Kane
Nicola Fulljames
as Dr. Beatrice Hearst
Patricia Merrick
as Dr. Julie Gilchrist
Jonathan Rigby
as Cummings
