When Paul Pennyfeather is unfairly expelled from Oxford University, he finds his only option is to go and teach at a substandard boarding school in rural Wales. There he meets a colourful cast of characters, including the alluring Margot Beste-Chetwynde, a wealthy widow with designs on the naeve Paul.

Valiantly taking the fall for the murky deeds of his fiancee Margot, Paul Pennyfeather finds himself in deep trouble with the law. Will Paul be able to escape imprisonment, and will Margot wait for him if he doesn't?