In HEART OF DARKNESS, Conrad's most existential hero, Marlow, is the commander of a riverboat looking for ivory to trade in the Belgian Congo. His journey into the heart of the Congo is both a thrilling adventure and a symbolic excursion into the depths of the human psyche to confront the evil that exists there. Marlow's encounter with the mysterious and corrupted Kurtz, who dies proclaiming the horror of what he found in the Congo, is the novel's defining moment, when Marlow recognizes his kinship with Kurtz's corruption. This insight enables Marlow to retreat from Kurtz's world and return to England. Kurtz, in his attempts to reconcile his noble ideas with his greed, can't survive. The Secret Sharer, one of Conrad's most celebrated stories, is about a ship's captain and his murderous double.