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.

'Producer stages outside broadcast despite jealous critic.' (British Film Catalogue)