'Dial A Deadly Number' saw Gary Collins make his third and final appearance in Thriller, having shone in 'Only A Scream Away' and 'The Double Kill'. This is a real slow-burner of an episode with a suitably languid pace that rolls along pulling various parts of the jigsaw together before a very satisfying and somewhat disturbing climax.
The plot relies on a clever contrivance involving a a misdialled telephone number - from which Dave Adams (Collins) takes advantage. He has been mistaken for a psychiatrist and decides to seize the opportunity of making some easy money from his clearly upset patient Helen Curry (played with the right degree of nervousness and fragility by Gemma Jones). She has been having nightmares within which she stabs a young man and is becoming alarmed at their ferocity and frequency. A number of facts emerge: Helen's sister Ann had a boyfriend called Paul Kirby, he has disappeared and his sister Sally has hired a private detective named O'Hara to search for him. This exercise proves to be fatal as O'Hara meets his death in the Curry house. By stabbing.
Adams' friend Tim is appalled by the deception and decides to reveal the fraud to Helen when she dials his number. In the interim Adams becomes romantically involved with Ann and learns a little more about the sisters' past and the strong influence of their mother - which has a significant bearing on the final outcome.....