William Golding: his life and work, philosophical outlook. Plan

Spoiler warning: Plot and/or ending details follow.
The novel begins with a large number of young boys, ages six to 12, stranded on a desert island. While being evacuated, their plane has been shot down. The first two characters introduced are Ralph, an athletic and charismatic boy, and "Piggy," a fat boy with glasses and asthma. The two boys obtain a conch and use it to call the other boys from across the island. The boys begin to discuss who should be their leader. Ralph and Piggy are the two obvious choices, but one other potential leader arises—Jack Merridew. Jack was a choir leader, and still acts as leader of the other castaway members of his choir. Ralph is elected as leader. Piggy is less popular than Ralph, but is intelligent, and becomes Ralph's "lieutenant." However, it is evident that Jack covets the leadership position. Ralph takes Jack and Simon, another choir singer, to explore the island. During their exploration they find a trapped piglet. Jack pulls out a knife, but hesitates, allowing it to escape. Jack vows never to hesitate again. Early on, the boys are full of optimism, expecting the island to be fun, despite the fact that many of the boys are scared of a "Beastie"—allegedly some kind of dangerous wild animal on the island seen by one of the younger boys with a birthmark on his face.
The boys then make their first attempt at being rescued by starting a signal fire (lit by Piggy's glasses). The fire burns out of control, and scorches half of the island. The boy with a birthmark on his face who saw the "Beastie" goes missing during the fire, and it is assumed that he died. Life on the island continues to deteriorate, becoming more and more disorganized. The major characters (Jack and Ralph) have conflicting aims for the island, and there are only two people, Ralph and Simon, willing to build shelters.
The island's descent into chaos starts, ironically, with the potential for rescue by a passing ship. Jack had led a group off hunting, taking with him the boys who were tending to the signal fire, so the ship sailed past without spotting the boys on the island. An intense argument ensues, in which a lens of Piggy's glasses is broken. Jack continues to push the boundaries of his subordinate role, and eventually becomes a tyrant. Ironically the sound of his choir was originally described as the "voices of angels," but the choir boys are later described as "demonic figures." Although the signal fire is maintained along with a false sense of security, the order among the boys quickly deteriorates as Jack and Ralph continue to struggle for power.
As the novel takes place during a war, a dogfight between two planes occurs over the island. One of the pilots parachutes out of his plane, but dies upon or before landing. Two twins, Sam and Eric ("Samneric," as they become known) assume that the pilot is the Beastie when they saw him in the dark, causing mass panic. An expedition to investigate leads to Ralph, Jack, and Roger, a choir boy, ascending the mountain, but they eventually run away from what they believe is the Beastie. Jack denounces Ralph as a coward, and calls for another election for chief, but does not receive a single vote. He leaves the group to create a new tribe. Most of the older boys eventually leave "Ralph's tribe" to join "Jack's tribe." This new tribe hunts down a pig, and they decide to host a feast. Before that, they sever the pig's head and place it on a stick as an "offering" to the Beastie. Flies swarm around the head of the pig. Simon comes across it, and through hallucination, the dead pig speaks to him. Its message foreshadows Simon's fate, and he runs down from the mountain to break the news about the dead pilot and his conversation with the "Lord of the Flies." However, in doing so, he is mistaken as the Beastie, and is beaten to death by the other boys.
Ralph's tribe dwindles in number. Jack's larger, less civilized tribe, however, needs to steal from Ralph's tribe to maintain their existence. They steal Piggy's glasses to light a fire. Piggy demands his glasses back, but is killed when Roger launches a boulder into him, crushing the conch shell and sending him over a cliff. Jack tries and fails to kill Ralph, and the next day, his tribe tries to hunt him down. In their pursuit, they start a forest fire, which is seen by a passing naval vessel, and one of the ship's officers comes ashore and rescues the boys. Ralph's brush with death is tinged with irony; Ralph had always pushed for a fire to be kept, but the fire that leads to their rescue was originally lit to kill him. For the first time on the island, Ralph cries, weeping for the "end of innocence," "darkness of man's heart," and his friend, Piggy.