What is the main conflict in A Wind in the Door by Madeleine L'Engle?

A Wind in the Door is the second in a four-part series of books by Madeleine L'Engle involving the Murry family. These timeless children's classics are remarkably ahead of their time in their use of cutting-edge science. L'Engle blends advanced scientific theory with spiritual mythology to create a magical yet oddly sensible world for her characters. Teenaged Meg Murry and her six-year-old brother, Charles Wallace Murry, are both highly intelligent, good-hearted children. Yet, their advanced knowledge of science, taught to them by their brilliant and famous scientist parents, leaves them feeling different and separated from their peers at school. As different as they are, they suffer all the normal childhood pangs and angst of trying to fit in with their peer group while remaining true to themselves.