It is very subtly indicated that the book takes place in the midst of an unspecified nuclear war. Some are ordinary students, while others arrive as a coherent body under an established leader (a choir). Most appear never to have encountered each other before. The book portrays their descent into savagery; left to themselves in a paradisiacal country, far from modern civilization, the well-educated children regress to a primitive state. At an allegorical level, the central theme is the conflicting impulses toward civilization—live by rules, peacefully and in harmony—and towards the will to power.
Different subjects include the tension between groupthink and individuality, between rational and emotional reactions, and between morality and immorality. How these play out, and how different people feel the influences of these, forms a major subtext of Lord of the Flies. In the midst of a wartime evacuation, a British plane crashes on an isolated island. The only survivors are all male children below age 13.
Two boys, the fair-haired Ralph and an overweight, bespectacled boy reluctantly nicknamed “Piggy” find a conch which Ralph uses as a horn.
Two dominant boys emerge during the meeting: Ralph, and Jack Merridew, a redhead who is the head of a choir group that was among the survivors. Ralph is voted chief, losing only the votes of Jack’s fellow choirboys. Ralph asserts two goals: have fun, and work toward rescue by maintaining a constant fire signal. They create the fire with Piggy’s glasses, and, for a time, the boys work together.
Jack organizes his choir group into the group’s “hunters”, who are responsible for hunting for meat. Ralph, Jack, and a black-haired boy named Simon soon become the supreme trio among the children.
Piggy, the most sensible of the bunch, is quickly outcast by his fellow “biguns” (the older boys) and becomes an unwilling source of mirth for the other children. Simon, in addition to supervising the project of constructing shelters, feels an instinctive need to protect the younger boys. The original semblance of order imposed by Ralph quickly deteriorates as the majority of the boys turn idle. At one point, Jack summons all of his hunters to hunt down a wild pig, including those who were supposed to be maintaining the fire. A ship approaches, but passes by because the signal fire has gone out.
Although the hunting of the pig turns out to be the hunters’ first successful hunt, Ralph is infuriated that they have missed a potential rescue. Around the same time, many of the young people begin to believe that the island is inhabited by a monster, referred to as “the beast”. Jack gains control of the discussion by boldly promising to kill the beast. Later, Ralph envisages relinquishing his position, though Piggy discourages him from doing so while the two of them and Simon yearn hopefully for some guidance from the adult world.
After Sam and Eric report possibly seeing the beast atop a mountain, Ralph and Jack investigate; they encounter the corpse and the open parachute of a fighter pilot who has landed on the island and mistake it as “the beast” asleep. Jack assembles the children with the conch and confirms the beast’s existence to them. The meeting results in a schism, splitting the children into two groups. Ralph’s group focuses on preserving the signal fire. Jack becomes the chief of his own tribe, which focuses on hunting while exploiting the iron-clad belief in the beast.
As Jack and the hunters have already slain their first pig, they offer promises of meat, fun, and protection from the beast. Jack’s tribe gradually becomes more animalistic, applying face to liberate their inner savages while they hunt. The face paint becomes a motif which recurs throughout the story, with more and more intensity toward the end. Simon, a part of Ralph’s tribe, who had “cracked” and went off looking for the beast by himself, finds the head of the hunters’ dead pig on a stick, left as an offering to the beast.
Simon envisions the pig head, swarming with scavenging flies, as the “Lord of the Flies” and believes that it is talking to him. Simon hears the pig identifying itself as the real “Beast” and disclosing the truth about itself—that the boys themselves “created” the beast, and that the real beast was inside them all. Simon also locates the dead parachutist who had been mistaken for the beast, and is the sole member of the group to recognize that it is a cadaver instead of a sleeping monster. Simon attempts to alert Jack’s tribe that the “beast” is nothing more than a cadaver.
While trying to tell Jack’s tribe of this fact, Simon is caught in a ring during a primal dance and Jack’s tribe beats him to death, with Ralph, Piggy, Sam, and Eric in the ring also. Ralph, Piggy, Sam, and Eric later try to convince themselves that they did not take part in the murder. Jack’s tribe then raid Ralph’s camp to steal Piggy’s glasses. Ralph’s tribe journeys to Jack’s tribe at Castle Rock to try to get back Piggy’s glasses. In the ensuing confrontation, Roger drops a rock on Piggy killing him and the conch is shattered. Sam and Eric are captured and tortured into joining Jack’s tribe.
Ralph is forced to flee. The following morning, Jack leads his tribe on a manhunt for Ralph. However, the fire and smoke attracts the attention of a nearby warship. Then a naval officer lands on the island near where Ralph is lying, and his sudden appearance brings the children’s fighting to an abrupt halt. Upon learning of the boys’ activities, the officer remarks that he would have expected better from British boys, initially believing them only to be playing a game. In the final scene, although now certain that he will be rescued after all, Ralph cries.