The black river of Lethe is a deadly, vaporous river that brings forgetfulness to those who cross it. Those who consume the water of the river or inhale its vapors either die or are driven insane. An elderly man lives on the shore near the river with his two companions: a deserting and brutish warrior, and a man who claims he used to be a prince but was most likely a slave instead. Like his two companions, the elderly man crossed the river at some point, but he knows neither his name nor his past, for the river stole his memories. When the three men find a sailboat and a corpse at the edge of the river, the elderly man sees the possibility for escape to the other side of the river, wanting to see what distant civilization might exist on the opposite shores and believing that crossing the river will return his lost memories to him. The warrior does not want to sail across the river and tries to prevent the elderly man from doing so, but the elderly man kills him. The elderly man tries to urge the prince to come with him, but the prince refuses and instead drinks the river's water. The elderly man sails across the river and reaches the other shore, realizing that he has regained none of his memories and his life has not changed at all.