Christopher John. When the Tripods Came. Tripods 4

New York, London: Simon & Shuster for Young Readers, 2003.
The novel was first published in 1988.The Tripods is a series of young adult novels written by John Christopher, beginning in 1967. The first two were the basis of a science fiction TV series, produced in the United Kingdom in the 1980s.
When the Tripods Came is a prequel written twenty years after the publication of the original trilogy. The plot follows the description of the conquest given in the second book of the main trilogy. Fearing the technological potential of humanity, the so-called 'Masters', unable to defeat humanity in a conventional war, hypnotise people through a television show called The Trippy Show, later using Caps to control them permanently. As in the original trilogy, the narrator of When the Tripods Came is a young English boy. As society slowly falls under the control of the Masters, he and his family escape to Switzerland, which has mounted the longest-lasting resistance. As the Swiss are themselves enslaved, the narrator and his family establish the "White Mountains" resistance movement of the original trilogy.