“Diego de Almagro” is a desert island, lost in the confines of Chilean Patagonia, latitude 52 degrees south. To be interested in this stone laid on the Pacific you have to be shipwrecked, crazy - or caver. The stakes for their expedition are high, starting with the construction of a 45 m2 cabin which will be the base camp for 20 teammates for two months. French, Chileans, cavers and scientists, veterans and newcomers. Braving the storms, they then go explore this island, on Bombard, or walking, diving in the resurgence and exploring deep chasms. The difficulties are permanent and the risks too, as evidenced by an accident that will mobilize the entire team for 3 days. But the findings are in unison. In sumptuous landscapes, austere but a wild beauty, men and women go from surprise to wonders. A great scientific and human adventure, told from the inside by a member of the expedition.