The famed fairly tale transcribed by the Brothers Grimm from ancient peasant legends has it that a legendary mountain of glass cannot be climbed. The protagonist of the tale discovers that for each step he takes up the mountain, he slides back two steps. To win his princess' love, he must climb the mountain so, cleverly, he turns about and climbs it backwards, gaining double elevation with each downward step. Perhaps the producers should have reversed the direction of this rather cumbersome film, which soars to the heights only in its music and scenery. The plot deals with British wartime airman Denison who, shot down in Italy's Dolomite mountains, is rescued by pretty partisan Cortese. Returning home to wife Gray, he attempts to compose an opera based on an ancient Dolomite peasant legend which obsesses him. Inspiration does not come readily in his domestic milieu; haunted by memories of the curvaceous, courageous Cortese, he returns to the scene of his wartime solace, where he completes his operatic opus. The successful premiere performance of the piece proves purgative of his passion; when Gray is injured in her own air crash, he returns to her long-suffering arms. Cortese's performance is outstanding; Denison and Gray, husband and wife in reality, handle their familiar relationship well, but the real stars of the picture are the music, with operatic baritone Gobbi, and the beautiful mountain scenery.