The thesis of this beautifully written essay is that one's existence is fleeting, while certain elements of life, such as the enjoyment of youth, continue forever for different generations. In this memoir, White returns with his son to the bucolic Maine lake where he summered as a child. He finds everything much the same, except he is experiencing it as a grownup instead of as a child. He writes of "living a dual existence." While he is saying or doing something, he imagines it is his father, not he, who is acting, and he sees his son doing what he used to do.

At the end of the story, as his son pulls on a wet bathing suit to go swimming in the lake after a strong thunderstorm, White says that "my groin felt the chill of death." He realizes at the end of the story that while the pleasures of the lake are the same to his son as they were to him as a child, he is now playing the role of the elder man. Soon, he realizes, his son will play the part of the adult, and he will no longer be around to play a role in life's eternal drama. 

The dominant impression of the short story concerns the passage of time and how memories fade in the face of change.  Adding to these impressions is the role of technology, the eroding nature of memory, and the passage of time changing the way White views his past memories of the lake.  The main idea of this work is that our ability to recollect is an intricate process that involves both positive and negative experiences.  Throughout the work, we see that White contrasts his tender memories of the lake as a youth with the complex emotions he undergoes examining the same lake as an adult.  The innocent joy as a child has been replaced with a growth of technology and a different conception of White's own identity as an adult examining the place of his childhood joy.