Plot synopsis: Lignes chronicles the sublime interplay between alpine literature and an expedition seeking the true meaning of mountaineering. Four high-mountain guides—Matthieu Maynadier, Pierre Labbre, Matthieu Détrie, and Julien Dusserre—embark on a project: to summit Nangpai-Gosum, an unclimbed 7,000-meter peak in Nepal, using the "alpine style" adapted to the Himalayas—the toughest and purest approach of all. Through this expedition, Lignes attempts to answer the question: "Why do we climb mountains?" Why, despite the harsh conditions and exhaustion, do these four Alpine guides pursue a perilous dream in a realm that belongs to no one? Lignes finds some answers in the past, drawing on 150 years of alpine literature. Serving as both narrator and seasoned guide, Raymond Renaud takes us on a tour of his books and speaks of the "conquerors of the useless"—from the turn of the century to the present day.