On a Sunday, 10-year-old Maël discovers a cute little white dog in front of his apartment door. When the owner cannot be found after an extensive search throughout the building, Maël is allowed to keep the dog. He names him Miezi. However, Miezi occasionally displays strange behavior: in the presence of certain people, he growls, barks, and bites. For the neighbor boy Laurent, the case is clear: Miezi is a racist! Maël and his parents are shocked, then embarrassed and outraged. Maël finds himself asking a series of questions: Can he still love his dog? Can someone be smart, nice, and racist at the same time? Can one unlearn being racist? And how can he explain to his classmates that only his dog, not himself, is racist? When Maël's aunt arrives with her family from the Antilles, Miezi's behavior threatens to lead to a family scandal.