Framing StoryDr Martin (Robert Powell) arrives at a secluded asylum "for the incurably insane" to be interviewed for a job by the wheelchair-using, authoritarian Dr Lionel Rutherford (Patrick Magee). Rutherford explains that he owes his current incapacitation to an attack by an inmate. Rutherford reveals his unorthodox plan to determine Martin's suitability for the post of head Doctor. One of the asylum's current inmates is Dr B. Starr, the former head doctor who underwent a complete mental breakdown. Martin is to interview the inmates of the asylum to deduce which one is Dr Starr. If his choice is correct Rutherford will "consider" him for the post.
　　The attendant Max Reynolds (Geoffrey Bayldon) admits Martin through the security door to the inmates' solitary confinement cells where he interviews each in turn.
　　"Frozen Fear"Bonnie (Barbara Parkins) recounts the plot to murder Ruth (Sylvia Sims), the wealthy wife of her lover Wal