PROBE: The Zero Imperative
1h 0m·Science Fiction, Action, Adventure·
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?
| Actor | Role |
|---|---|
 Caroline JohnDr. Elizabeth Shaw | Dr. Elizabeth Shaw |
 Jon PertweeDr. Jeremiah O'Kane | Dr. Jeremiah O'Kane |
 Sylvester McCoyDr. Colin Dove | Dr. Colin Dove |
 Colin BakerPeter Russell | Peter Russell |
 Mark GatissDr. William Bruffin | Dr. William Bruffin |
 Louise JamesonPatricia Haggard | Patricia Haggard |
 Sophie AldredPublic Relations Officer | Public Relations Officer |
 Linda LusardiLouise Bayliss | Louise Bayliss |
| DDavid TerenceDaniel O'Kane / Eustace O'Kane | Daniel O'Kane / Eustace O'Kane |
| NNicola FulljamesDr. Beatrice Hearst | Dr. Beatrice Hearst |
| PPatricia MerrickDr. Julie Gilchrist | Dr. Julie Gilchrist |
 Jonathan RigbyCummings | Cummings |
 Alexander KirkOrderly | Orderly |
| DDaniel MillsGhostly Child Voice | Ghostly Child Voice |
 Peter DavisonPatient One | Patient One |