The film begins in a BBC studio with the 100th edition of "In Town Tonight". Flotsam and Jetsom open with a "topical number". Then there is an interview with a distinguished actor, which dissolves into a performance of one of his famous melodramas about a wicked moneylender etc.
Romeo and Juliet in 1930s England. The owner of the mill and the local lord are in conflict over water rights. The lord wins threatening the mill owner with financial ruin.
Undercover agent Robert Leyland entraps crooks trying to sneak expensive goods past customs on transatlantic crossings. After Leyland falls for reluctant smuggler Barbara Standish, he convinces her to return with him to France with her cache of diamonds. But she is unaware of a network of thieves onboard their ship, competing against each other to make off with her jewels.
