Jean des Bossons is a documentary-fiction which recounts the activities of a high mountain guide in 1947. Around Chamonix Mont-Blanc, the guide Jean des Bossons, interpreter by the mountaineer Armand Charlet, accompanies on mountain hikes, Jean-Pierre, an apprentice guide. The novice, skis on the shoulder, is already clumsy. The professional taught him how to travel on skis uphill and downhill, then mountaineering in ice and rock parishes. By dint of training, Jean-Pierre has made it his job. Guides are also lifeguards. A group went to a glacier to rescue a man who had fallen into a crevasse. During this rescue, Jean des Bossons is the victim of an accident. A drama that prevents him from practicing the profession, but not climbing. The man sinks into the fog and Jean-Pierre cannot find him.