The story evolves around a radio panel game show "Twenty Questions." The panel is challenged with an anonymous question. The answer leads to a series of murders in which the killer uses the programme to name his victims in advance. Two reporters spot a link between them and enlist the aid of the panel in trapping the guilty party.
Bob Beacham

Mary Game

Tom Harmon

Det. Insp. Charlton
Olive Tavy

Self - The Twenty Questions Team
Self - The Twenty Questions Team guest artiste

Self - The Twenty Questions Team
Self - The Twenty Questions Team
Self - The Twenty Questions Team 'Mystery Voice'
Self - The Twenty Questions Team

Maurice Emery KC
Echo News editor

Mohammed Ali
Gen. Maitland

Stewart MacPherson's secretary
Police Commissioner

Police Officer 'Tiny' White
John Grimshaw

Record News editor

Cheshire Cheese waiter
Doctor

Mrs. Tavy's Neighbour (uncredited)

Frederick 'Ricky' Tavey (uncredited)