Nénette is a little girl who is sixty years old. A problem at birth has made her different. Nénette, who has the mental age of an 8-year-old, has always lived with her mother, who raised her alone. Nénette works, cleaning the community school, and her best friend is a tortoise. But when her mom dies, everything will change for Nénette, and she must move into a retirement home. But, as the institution doesn't accept animals, Nénette sets out with her suitcase and her tortoise, planning to find her father, whom she knows only by a yellowed photograph, a letter and an address. When Nénette finally arrives at the address indicated on the letter, she discovers a drugstore. There's no dad, but there is her father's son Paul Bérard, an uptight druggist, who is alarmed by his half-sister's unexpected arrival on the scene.