A plane carrying a number of British schoolboys fleeing the conflict is brought down over a desolate tropical island as it is in the process of evacuating them. Ralph and Piggy are the ones who find a conch shell on the beach, and Piggy is the one who has the bright idea that they could use it as a horn to call the rest of the lads. After coming together, the boys immediately set to work choosing a leader and coming up with a plan for their escape. They decide that Ralph will be their leader, and Ralph chooses Jack to be in charge of the guys who would go out and find food for the entire group.
In order to learn more about the island, Ralph, Jack, and another child named Simon embarked on an adventure together. Ralph makes the announcement once they have returned that they need to start a signal fire in order to draw the notice of passing ships. The boys are able to light some smouldering wood by directing sunlight through the lenses of Piggy’s eyeglasses, which helps them achieve their goal. However, the boys are more interested in playing than they are in keeping an eye on the fire, and as a result, the blaze spreads swiftly and consumes the entire forest. One of the younger boys in the group is reported missing after a big area of decaying wood catches fire and becomes out of control. It is presumed that he was killed in the fire.
At first, the lads have a good time being left to their own devices and spend much of their time frolicking around in the water and participating in various games. Ralph, on the other hand, grumbles that they should be tending to the signal fire and constructing tents in order to take shelter. The hunters are unsuccessful in their attempt to capture a wild pig, but Jack, the head of the group, is becoming more and more consumed with the activity of hunting.
Ralph and Piggy are horrified to see that the signal fire, which had previously been the responsibility of the hunters to keep, has gone out one day when a ship appears on the horizon. Ralph, infuriated, rushes over to confront Jack, but the hunter has just returned with his first kill, and all of the hunters appear to be consumed by an unexplainable frenzy, reenacting the pursuit in a kind of mad dance. Ralph’s anger is palpable. When Piggy criticises Jack, Jack responds by punching Piggy in the face. Ralph blows the conch shell in an attempt to restore order, and then gives a speech to the boys in which he reprimands them. During the course of the meeting, it is immediately apparent to everyone that a few of the lads have begun to feel scared. Since the beginning, the youngest boys, who are referred to as “littluns,” have had difficulties sleeping due to recurring nightmares, and an increasing number of the boys now believe that there is some kind of beast or monster hiding on the island. The elder lads make an effort to persuade the others in the gathering to think in a logical manner by asking where such a creature might possibly hide during the daytime. One of the littluns puts out the terrifying hypothesis that it could be hiding somewhere in the water, which sends shivers down the spines of the other members of the party.
Shortly after the conference, there is a combat between some military jets that takes place high above the island. The guys, who are currently sleeping below, are unaware of the explosions and flashing lights that are occurring in the clouds. On the mountain known as Signal Fire, a deceased parachutist falls to the ground. The twins Sam and Eric, who were tasked with keeping watch over the fire throughout the night, are sound asleep and thereby miss the landing of the parachutist. When the twins come to, they notice the massive shadow of his parachute and hear the peculiar noises it makes as it flaps. Fearing that the island monster is about to attack them, they flee back to the camp in a panic and report that the beast has already attacked them.
The young men plan a hunting trip in order to look for the monster. Jack and Ralph, who are getting into more and more arguments, decide to climb the mountain together. When they see the silhouette of the parachute from a distance, they have the impression that it is a monstrous gorilla with a twisted face. At the subsequent meeting, Jack and Ralph share their experience with the sighting with the other members of the organisation. Jack asserts that Ralph is a coward and that he ought to be removed from government; nevertheless, the other lads refuse to vote to remove Ralph from authority despite Jack’s assertions. Jack becomes enraged and begins to flee along the beach, yelling for the other hunters to follow him. Ralph rouses the other boys to construct a fresh signal fire, but this time it will be built on the beach rather than on the mountain. They comply, but before they have done the work, the majority of them have already escaped to join Jack.
In order to mark the event, Jack organises a hunt as well as the brutal and ritualistic death of a sow. He then proclaims himself to be the leader of the newly formed tribe of hunters. The head of the sow is then placed on a stake in the jungle that has been sharpened as an offering to the animal after it has been beheaded by the hunters. Later on, when he comes across the head that is covered in flies and blood, Simon has a horrifying vision in which it appears to him that the head is trying to communicate with him. The voice, which he believes to be that of the Lord of the Flies, tells him that Simon will never be able to get away from him because he is present in every man. Simon faints. As soon as he comes to, he travels to the mountain, where he comes across the body of the deceased parachutist. Simon then decides to travel to the beach to inform the other boys about what he has seen after coming to the realisation that the beast does not exist in its traditional form outside of each individual boy. When the others see Simon’s shadowy figure emerge from the jungle, they rush at him and kill him with their bare hands and teeth. Even Ralph and Piggy have joined Jack’s feast at this point.
Ralph and Piggy have a conversation about what they have done the following morning. Jack’s pursuers ambush them and the few people who are following them, and in the process, they take Piggy’s glasses. Ralph and his companions travel to Jack’s stronghold in an effort to talk some sense into him, but instead of listening, Jack has Sam and Eric restrained and begins a fight with Ralph. During the subsequent conflict, one of the boys named Roger rolls a boulder down the mountain, which results in the death of Piggy and the destruction of the conch shell. Ralph only narrowly avoids being pierced by a barrage of spears.
Ralph goes into hiding for the remainder of the night and throughout the next day as the others hunt him down like an animal. In order to coax Ralph out of his hiding place, Jack instructs the other guys to set fire to the surrounding woodland. Ralph chooses to remain in the jungle, where he finds the sow’s head and destroys it. However, he is finally dragged out onto the beach, where he is aware that the other lads will soon approach to kill him. Ralph passes out from tiredness and when he recovers enough to look up, he sees a British navy commander standing over him. Ralph is shocked. The officer’s ship saw the fire burning in the bush and notified the officer. When the other boys finally get to the shore, they freeze in their tracks when they see the officer there. Ralph is questioned by the police because he is mystified by the sight of these band of barbaric children who are thirsty for blood. Ralph is elated by the realisation that he is unharmed, but as he considers everything that took place on the island, he starts to cry. The other lads start crying as well at this point. The officer steps away from the group so that the kids can collect themselves and continue.