Young Will Parker and his companions make a perilous journey toward an outpost of freedom where they hope to escape from the ruling Tripods, who capture mature human beings and make them docile, obedient servants. Long ago, the Tripods -- huge, three-legged machines -- descended upon Earth and took control. Now people unquestioningly accept the Tripods' power. They have no control over their thoughts or their lives. But for a brief time in each person's life -- in childhood -- he is not a slave. For Will, his time of freedom is about to end -- unless he can escape to the White Mountains, where the possibility of freedom still exists.