The story itself takes place on an isolated island. A plane has crashed (though this plane is never mentioned nor seen again for the rest of the story), and it transpires that there are no adult survivors. Two English boys including the fair-haired Ralph and an overweight, bespectacled boy deemed "Piggy" form the initial focus, as they begin to make sense of their new surroundings. The boys soon find a white conch shell and Piggy suggests that Ralph use the conch as a horn to call for any other survivors who might be nearby. Ralph, thus, initiates the island's first assembly where all of the survivors are revealed to be male children, none seemingly over the age of thirteen: "biguns" (a few older boys) and "littluns" (several younger boys).
The survivors rapidly side with one of two dominant boys: Ralph, and another older boy named Jack Merridew (the head of a choir group that also landed on the island, presumably in the same plane crash). A brief election is held among the children and Ralph is voted chief (losing only the votes of Jack's loyal fellow choirboys) and he calls everyone together to work toward two common goals, the first being to have fun and the second to be rescued by creating a constant fire signal, to be lit using Piggy's glasses. For a time the boys work together towards building shelters, gathering food and water, and keeping the fire going. The choirboys then create their own goal, to become the hunters of the local animals.
Jack, a bony, freckled redhead, becomes an immediate threat to Ralph's leadership, obviously envious of Ralph's ascent to chief, and empowers himself instead by becoming the unanimous leader of the hunters. Together, Ralph, Jack, and a black-haired boy named Simon, become the supreme trio among the children, going on a short expedition to confirm that they are indeed on an island. Piggy, the most sensible of the bunch, is quickly outcast by his fellow biguns and becomes an unwilling source of laughter for the other...