Margot and the other children live and go to school together on Venus. Their parents are part of some undisclosed program that is working to create a civilization on Venus. On Venus, it rains continuously day and night for years on end. However, once every seven years, the sun shines for two hours.
Compared to the other children, Margot has been on Venus a relatively short time. Previously she lived on Earth and remembers it well. Supposedly on Earth, the sun still normally shines. Margot has seen and experienced the sun. The other children were born on Venus and the last time they saw the sun, they were only two years old so they do not remember it. To them, the sun is a myth and many are unsure it even really exists.
When the other children hear Margot describe the sun and say that she has seen it, they do not believe her. Margot already seemed to be an outcast, different and withdrawn from the others. Once she speaks of knowing the sun, the children actively shun her, eventually pushing and shoving her. Her descriptions are vivid and the author leaves the reader to assume that as Margot speaks, the children start to believe her and to resent her.