|Monsieur Duval asks Anatole to watch over his wife’s birthday present, a priceless pearl necklace. When a thief breaks into the factory to steal the necklace, Anatole and Gaston are launched on a night full of adventure. Not wanting to let Duval down, Anatole is determined to retrieve the necklace and return it to Madame Duval in time for her birthday party. As always, Charlemagne does his best to hamper their efforts, but in the end the mice prevail. Meanwhile, at home Paul and Paulette are babysitting the other children for the very first time and learn the importance of responsibility and of seeing a task through to the end.