John Forrest, an insurance investigator with a weakness for model railways, is on the trail of a gang of smash-and-grab thieves targeting Europe's most prestigious jewellers. As the chase leads him to Ireland, Forrest finds he needs help and who better to call upon than his impossibly elegant, highly capable wife, Alice?

Old Mother Riley is a British comedy film directed by Oswald Mitchell and starring Arthur Lucan, Kitty McShane, Barbara Everest, Patrick Ludlow and Hubert Leslie. Mother Riley and her daughter stop the plans of some disinherited relatives to overturn the terms of a will. It was the first in the Old Mother Riley series of films.

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.