The main characters are Ralph, Piggy, and Jack. Suddenly, they find themselves stranded on an island, without grownups, and run around freely without rules.
Ralph and Piggy want to escape the island, as they realize the danger. They figure that the best way to do this is to keep an ongoing fire that will signal any passing boats. However, this is harder than they think.
Jack and his hunters are supposed to keep the fire alive and burning, but they instead spend their time goofing around, hunting and killing any pig that they find. This results in the fire burning out, and leads to conflict.
Somehow, through wars, killing, hunting, and betrayal, the fire is kept alive, and a marshal rescues the boys seeing the signal.