The accident of the mountain guide Joseph, the patriarch of Servettaz, marked the spirits. His son Zian decides to take up the torch. Married to Bianca, the daughter of the wealthy Milanese industrialist who accompanied her father in the ascent of the Drus, Zian lives his great love story, a three-way love story, the mountain always remaining the most demanding mistress. Tired of the agonizing expectations and loneliness during her husband's climbs, Bianca returns to Italy. Zian will join her, but the society life of the Milanese bourgeoisie is far from his values ​​and he returns to his mountains, to Chamonix. During a chamois hunting trip in the mountains, Zian falls into a crevasse. Bianca, alerted by a presentiment, returns to the one she loves above all...