Young aspiring actress Molly Lester witnesses a double murder, so its perpetrator, a killer known as The Dark Man, tries everything to maintain her silence.
| Actor | Role |
|---|---|
 Edward UnderdownDetective Inspector Viner | Detective Inspector Viner |
 Maxwell ReedThe Dark Man | The Dark Man |
 Natasha ParryMolly | Molly |
 William HartnellSuperintendent of Police | Superintendent of Police |
 Barbara MurrayCarol Burns | Carol Burns |
| RRobert LongCharles Burns | Charles Burns |
 Cyril SmithSamuel Denny | Samuel Denny |
| LLeonard WhiteDetective Sergeant Evans | Detective Sergeant Evans |
| EErnest HainesMostyn | Mostyn |