On May 25th, the world renowned Ballet de l'Opéra National de Paris performed its first choreography by Anne Teresa De Keersmaeker, 'Rain'. It proved a difficult task to translate her dance language to the classically trained ballet dancers. Ballet's rigidity had to be replaced by a different kind of severity: the mathematical formula of 'Rain', which hides several complex layers of emotions. This poetic documentary allows for a unique look behind the scenes of the production.