What is the dramatic situation at the beginning of the novel?

On a tropical island, a twelve-year-old boy with fair hair is climbing out of plane wreckage (referred to as "the scar") on a beach and towards a lagoon. He faces another child around his age, a fat boy with glasses. The two, who have not previously met, begin a conversation. The fair-haired boy introduces himself as Ralph, while the heavy boy accidentally reveals his nickname at school: "Piggy." Against the other child's protestations, Ralph insists on calling him Piggy. Through their conversation, it is revealed that the boys have survived a plane crash in the Pacific Ocean, and no adults are present among the survivors. They confirm that both the pilot and "the man with the megaphone"-perhaps some sort of rescue worker-both died in the crash. The boys appear to have been escaping from an atomic war in their country, a place referred to only as the Home Counties (signaling England).