While travelling in Switzerland, the child of a well-off couple is kidnapped. She is held to ensure that her father does not reveal what he knows about a planned assassination.
Since they can't talk to the authorities, the parents plan to begin the search for their daughter on their own.
This is the original, British-made movie from 1934 and is now in the public domain. After coming to the United States, Alfred Hitchcock produced a remake of this movie in 1956 starring James (Jimmy) Stewart and Doris Day. The remake remains under copyright.