The story begins with Neddy Merrill lounging at a friend's pool on a mid-summer's day. On a whim, Neddy decides to get home by swimming across all the pools in the county, which he names "The Lucinda River" in honor of his wife, and starts off enthusiastically and full of youthful energy. In the early stops on his journey, he is enthusiastically greeted by friends, who welcome him with drinks. It is readily apparent that he is well-regarded and from an upper-class or upper-middle-class social standing.
Midway through his journey, things gradually take on a darker and ultimately surreal tone. Despite everything's taking place during just one afternoon, it becomes unclear how much time has passed. At the beginning of the story it was clearly mid-summer, but by the end all natural signs point to the season's being autumn. Different people Neddy encounters mention misfortune and money troubles he doesn't remember, and he is outright unwelcome at several houses which should have been beneath him. His earlier, youthful energy leaves him, and it becomes increasingly painful and difficult for him to swim on. Finally, he staggers back home, only to find his house decrepit, empty, and abandoned.