In the rebellious northern frontier province of colonial India, British Army Captain Scott, a young prince and the boy's governess escape by an obsolete train as they are relentlessly pursued by Muslim rebels intent on assassinating the prince.
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.
A seasoned pilot is condemned for an error which causes a crash. The pilot later dies in a crash with similar circumstances and an examiner looks for scientific reasons for the crashes.
