Documentary stories of children in a stage production, told not with pity or melodrama but through beauty and the superpower of children with rare diseases. Illness is spoken of through the lens of rarity itself: in life, in nature, and in a person. The film is conceived as a backstage record of the making of a play called Rare. The main characters are on stage; in the auditorium and at rehearsals are those who watch and guide them in real life — leading Russian geneticists, doctors specialising in rare diseases, and parents.