Former U.N.I.T luminary Liz Shaw (Caroline John) and her assistant Bayliss (Linda Lusardi) are investigating a series of bizarre murders: all committed near to a soon-to-be-closed psychiatric hospital.
When the hospital is unexpectedly reprieved by industrialist Peter Russell (Colin Baker) events seem to move out of Liz's control. Are the incumbent director of the clinic Doctor Dove (Sylvester McCoy) and his predecessor Doctor O'Kane (Jon Pertwee) harbouring the killer? What is the centuries-old horror hidden in the hospital grounds? And what exactly is the secret of Room Zero?
This exciting psychological thriller features three former Doctor Who's (Jon Pertwee, Colin Baker, Sylvester McCoy) and three of their assistants (Caroline John, Louise Jameson and Sophie Aldred) as well as Linda Lusardi in her first film role.