When Henry and Beanpole remove the device, a nearby Tripod attacks them, but the boys defeat the Tripod and elude subsequent efforts to find them. The novel climaxes with Henry and Beanpole discovering that earlier, when Will was captured by a Tripod, he was unknowingly implanted with a tracking device. He is accompanied by his cousin Henry and later by a French teenager named Jean-Paul Deliet, nicknamed 'Beanpole'. Protagonist Will Parker, a thirteen-year-old boy living in the fictional English village of Wherton, is looking forward to being Capped at the next Capping Day, until a chance meeting with a mysterious fake-Capped man named Ozymandias (taking his name from a poem he frequently recites) prompts him to discover a world beyond the Tripods' control. Life is like the Middle Ages in the pre-industrial era, except that all adult humans are subject to Tripod control.

According to The City of Gold and Lead, Masters begin to believe that humans should be capped at an earlier age 'because some humans, in the year or two before they are Capped, become rebellious and act against the masters', but this cannot be done, because Capping must wait until the braincase has stopped growing. Some people, whose minds are broken by the Caps, become vagrants. Humans are controlled from age 13 by implants called 'Caps,' which suppress individuality and free will. Lifestyle is reminiscent of the Middle Ages, but small artifacts from the Modern Age are still used, such as watches. Human society is largely pastoral, with few habitations larger than villages, and what little industry exists is conducted under the watchful presence of the Tripods. The story of The Tripods is a variation on post-apocalyptic literature, wherein humanity has been enslaved by 'Tripods' - gigantic three-legged walking machines, piloted by unseen alien entities (later identified as ' Masters'). The first two were the basis of a science fiction TV series, produced in the United Kingdom in the 1980s.

The Tripods is a series of young adult novels written by John Christopher, beginning in 1967. JSTOR ( May 2015) ( Learn how and when to remove this template message).Unsourced material may be challenged and removed. Please help improve this article by adding citations to reliable sources. This article needs additional citations for verification.

The Tripods Trilogy by John Christopher