A professor teaching at a correspondence school discovers that a Nazi agent is trying to prevent a trade treaty being signed between England and South America.

Davey Fenwick leaves his mining village on a university scholarship intent on returning to better support the miners against the owners. But he falls in love with Jenny who gets him to marry her and return home as local schoolteacher before finishing his degree.

Scotland Yard sends a handwriting expert to a country house full of people with guilty secrets in order to solve a murder.