The central conflict in “All Summer in a Day” concerns Margot’s difference from the other children—the fact that she was born on Earth rather than on Venus and consequently remembers and misses the sun. It’s this difference that Bradbury identifies as the root cause of the other children’s bullying, and when they lock her in the closet, it’s a direct reaction to her obvious desire to see the sun again: “[T]he biggest crime of all was that she had come here only five years ago from Earth, and she remembered the sun and the way the sun was and the sky was, when she was four, in Ohio” (Paragraph 29).

To understand why the children respond to Margot’s difference with such hostility, it’s helpful to consider the work’s setting. Bradbury doesn’t provide many details about the kind of society the colonists have built on Venus, but what he does say suggests that it’s a society that values group cohesion; Margot, for instance, routinely hears the other children making small noises in their sleep, which implies that they all share a dormitory or other communal living space.