When Sylvain Tesson left the colourful yellow houses of the French Riviera for a ski trek across the Alps with his friend, a high-altitude mountain guide, he didn't know what exactly awaited him. The trek would turn into an extraordinary adventure.

Over the course of four years they ascended high into the Alps in winter, following the curve of the mountains from the Mediterranean to the Adriatic, immersing themselves in a strange white world made entirely of snow. In the bitter cold and overlooked by an empty sky, only the effort of moving forward, one difficult stride at a time, separated the days from one another. And as they trudged onwards, the never-ending white of the high Alps cancelled out all feelings - hope, fear, memory and regret.

What did he stand to gain by inflicting this ordeal on himself? This was no ordinary mountain trek: it was a search for communion with the magic substance of the White.