Three teenage girls in an incomplete triangular relation. The base of the triangle is barely there. At the apex is Marie, a serious, short and lean tomboy with a Belmondo-like facial structure. Her best friend is the physical and psychological opposite: coquette, chubby -- I dare say fat -- and desirous for her first kiss with a boy but not quite ready for her first sexual encounter. Because of her chubbiness, boys don't seem interested and it pains her.
The other leg of the apex is a beautiful "fille fatale" blonde vamp. She is deeply involved in the sport of synchronized swimming performing at competitive level. Marie sees her during a competition at the local public swimming pool. Marie insinuates herself into the life of the vamp using the desire to become a synchronized swimmer as an argument. The vamp has a reputation of being a whore, making out with any young male that orbits around her. Marie is not phased out by that reputation. Put a stress on reputation.
The first half is set up. We get to see a lot of synchronized swimming as we become familiar with the three girls. Eventually the narrative leaves synchronized swimming behind and concentrates on the topsy-turvy relations among the three. That's when unexpected things start to happen.
It is a trademark of French films to drop nuggets of wisdom on the viewer. This one is no exception. Here it is about ceilings and the dying. See the film to learn more.
The director says that the use of synchronized swimming is purposeful. That women-only sport is a metaphor for a girl's life: pretty and feminine on the surface while hard working and competitive underneath. A number of scenes drive this point: elegant moves and smiles for the public, legs kicking ungainly underwater. The title in French is also suggestive: "prieuve", or octopus, suggest an individual having to juggle many pressures simultaneously.