Louis, a timid nine-year-old boy from Paris, spends his summer vacation in a small town in Brittany. His mother Claire has lodged him with her girlfriend Marcelle and her husband Pelo while she is having her second baby. There Louis makes friends with Martine, the ten-year-old girl next door, and learns about life from her . His subsequent adventures run the gamut from delightful to terrifying, with a little "coming of age" (via a few glimpses of nudity) thrown in.