A climatologist, a physicist, and a volcanologist set out to conquer the highest peak in the Alps. Through exceptional images, the film recounts their odyssey and reveals the immense wealth of this natural laboratory. Straddling France, Italy, and Switzerland, the Mont Blanc massif was formed 240 million years ago. Four times the size of Paris, it covers 400 km2. Its summit, the highest in Western Europe, rises to 4,810 meters. Three scientists begin its ascent: Martine Rebetez, a Swiss climatologist; Étienne Klein, a philosopher and physicist at the French Atomic Energy Commission; and Jacques-Marie Bardintzeff, a geologist and volcanologist. Advancing in two roped teams, they are accompanied by Jean-Franck Charlet and François-Régis Thévenet, mountain guides, as well as physiologist Hugo Nespoulet.