When Sylvain Tesson left the colorful yellow houses of the French Riveria for a ski trek across the Alps with his friend Daniel du Lac, a high-altitude mountain guide, he didn't know what exactly would await him. Over the course of four years, from 2018 to 2021, they ascended high into the Alps in winter, following the curve of the mountains from the Mediterranean to the Adriatic, entering into a white world entirely of snow, bitterly cold, and overlooked by an empty sky; only the effort of moving forward, one stride at a time, separated the days from one another. He thought he was venturing into beauty but he was immersing himself in a substance. In the white of the high Alps all is canceled out—hopes, fears, memories, and regrets. What did he stand to gain by inflicting this ordeal on himself? This was no ordinary mountain trek: it was communion with a substance. Perhaps his longtime dream of transforming travel into prayer would come true at last.