A veteran mountaineer begins a journey on foot and against the current around the Esla River and its tributaries. While he walks, he recalls the teachings of the person who discovered him in his youth, his recently deceased teacher and friend. Throughout your journey through the river of memory we will get to know a good part of the Leonese territory and its natural and cultural heritage. In addition to that trip, there will be another interior: we will share the traveler's reflections on friendship, the passage of time, the coherence or incoherence between our ideas and our actions and their repercussions on nature and on our own survival.