When Loulotte, a Parisian sculptor, is invited to show her works in Venice, she asks her former nurse, Bécassine, to leave Brittany to come and take care of Charlotte, her 10-year-old daughter, until her husband, Edmond, a wildlife photographer, returns from the North Pole. However, when Edmond returns, he shows Gaspard, an antique dealer, a jewel he found on an archeological site up north. Convinced that the jewel is Viking treasure, Gaspard orders Gari and Baldi, his henchmen, to hide the archeological site, after they do away with Edmond. To save Charlotte’s father, Bécassine finds herself on a treasure-hunting trip that takes her around the world.