Mont Blanc: summer of 1961. Three Italian climbers, led by charismatic Walter Bonatti, meet four French colleagues, led by Pierre Mazeaud, completely by chance at the Fourche campsite on the French-Italian border. They’ve decided to be the first to climb the Pillar of Frêney, a pillar of rock 750 metres high at the summit of the Mont Blanc. It’s an extremely difficulty climb. Circumstances force them to proceed together, even if carrying out an endeavor like this isn’t easy with seven people. They’re only one hundred and twenty metres short of the top, but suddenly a violent tempest arrives: gusts of wind, flurries of snow and hellish lightning that rattle the mountaineers. The seven organise themselves on three ledges, which is to say two little terraces of granite, waiting for the storm to pass. They only need a few hours to reach the summit and then, descending, the cabin at Vallot. However, the storm progressively gets worse, continuing for four days and nights. At the end of the fourth day, seeing that his companions are almost spent, Bonatti takes the initiative and starts to descend, opening up the path to survival.