Following in the footsteps of Frison Roche, 7 climbers explore the main Hoggar massifs in Algeria. Their main objective is the ascent of the Garet El Djenoun summit via the north ridge, a long climb symbolic of a certain difficulty and a significant commitment, due to its location in the desert. They also attempt the Diedre Agresti, a daring route from the 70s, opened in around ten days on artificial, and unequipped; it is a path that has never been repeated; the objective is to do it free and almost only on wedges, with difficulties up to 7b/c in a sometimes very delicate rock... Excerpts from the film shot in 1970 by Henri Agresti on this same route, allow us to compare the technical and material means of the time to those of today. They also discover the beauty of the Algerian desert, its silence, its rock paintings, the customs of the Tuaregs, etc... a fascinating journey.