Chamonix in the 1930s was a resort where a cosmopolitan, fashionable and sporting society thronged, in search of novelties and thrills found in mountaineering. These people rub shoulders with the Chamoniards but do not meet except on the trails of Mont-Blanc. The accident of Joseph, the patriarch of Servettaz, guides from generation to generation, marked the spirits. It is his son Zian who decides to take up the torch. Married to Bianca, the daughter of the wealthy Milanese industrialist who was partly responsible for her father's death, Zian lives out her great love story - a threesome - with the mountain always remaining the most demanding mistress. Tired of the agonizing expectations and loneliness during her husband's ascents, Bianca returns to Italy, Zian joins her, but society life is not his world, he returns to Chamonix. During an outing in the mountains, Zian falls into a crevasse. Bianca, alerted by a presentiment, returns to the one she loves above all...