Ada Harris, a cheerful middle-aged cleaning lady in 1950s London, is enamoured with her employer’s couture wardrobe and becomes determined to buy her own Christian Dior gown. She works her fingers to the bone to earn extra pennies and risks her savings on an all-or-nothing bet. She wins! She ventures to Dior in Paris and chooses her dream creation, and makes lifelong memories on her adventure. Returning to London, her generosity leads her to lend her prize possession to a young actress, but disaster strikes!