A pianist arrives in her new flat. But as soon as she rehearses, her neighbour tries everything possible to stop her from playing. The reason : she hates classical music. Soon enough, a sound war starts between the two women, very rapidly involving everyone in the building. When the police arrive, they witness a crowd of hysterical neighbours shouting at each other and take the side of the pianist, the only one who at that moment, after a moment of intense madness, is playing a serene Mozart piece.