The Tripods franchise first came to being through a series of young adult novels written by John Christopher, a trilogy followed by a prequel. The first book, The White Mountains, was written 1967 while the second and third were written a year later in 1968. The first two books were adapted into The Tripods TV series. A fourth book, When the Tripods Came, was written as a prequel after the TV series was cancelled, 20 years after the publication of the original trilogy.
The Tripods novels told a post-apocalyptic story, where humanity has been conquered and enslaved by gigantic three-legged machines called Tripods. Although it is not revealed till the second book, these Tripods are controlled by an alien race called Masters. Human society has returned to a medieval society, living in small villages. At the same time small artifacts from the modern age are used, giving everything an anachronistic appearance.
Humans are controlled from the age of 14 by implants called Caps, which suppress curiosity and creativity. Caps leave the recipients placid and docile, incapable of dissent. People who are capped are happy to leave home and serve the Tripods. The caps cause them to follow the Tripods' will. Some people, whose minds are broken under the pressure of the cap's hypnotic power become vagrants, who wander the countryside. The Capping can only be performed after the age of 14 since that is when the braincase has stopped growing.
In the future, the world is controlled by three-legged machines called Tripods. Life goes on largely as it had in the pre-industrial era, as all of humanity is subject to mental controls that prevent anyone from challenging the established order. Will, a thirteen-year-old boy living in the small English village of Wherton, is looking forward to the transition to adulthood, to take place on the next Capping Day, until a chance meeting with a mysterious Vagrant named Ozymandias sends him on a quest to discover a world beyond the Tripods' control. He is accompanied by his cousin Henry, and a French teenager named Jean-Paul, nicknamed "Beanpole" for his height and slimness, and punning similarity to his real name.
On their journey the boys have many adventures, such as travelling through the ruins of Paris or staying at a castle. The novel climaxes with Henry and Beanpole discovering that earlier, unbeknownst to them, Will was captured by a Tripod and implanted with a tracking device. They realise the tripods intend for the boys to lead them to the human resistance. Henry and Beanpole remove the device, which causes a nearby Tripod to attack the group. The boys defeat the Tripod and eventually reach, and offer their services to, the resistance, located in the titular White Mountains.
After a year among the free men in the White Mountains, the resistance charges Will, Beanpole and a German boy, Fritz, wearing realistic-looking yet harmless caps, to infiltrate a Tripod City by competing in a regional sporting exhibition: the winners of the events are always offered to the Tripods for service. Will, a boxer, and Fritz, a runner, win their respective contests, while Beanpole fails to win in the jumping events.
The winners are taken by Tripods, which they discover to be machines operated by living creatures, to the Tripod city in a pressurised dome astride a river. Inside the city, the boys are confronted with the actual aliens, whom they refer to as the Masters. Human males are slaves inside the cities, while beautiful females are killed and preserved for the Masters to admire. Slaves are furnished with breathing masks to survive the aliens' lethal atmosphere, but the artificially increased gravity inside the cities rapidly wastes them away, so fit new slaves are selected at the annual sporting competitions to replace those who have weakened and died.
While Fritz is severely abused by his Master, Will learns much about the aliens' origins and habits from his Master. Eventually the Master reveals a plan to replace the Earth's atmosphere with the Masters' toxic air to enable the Masters to assume full control of the planet. When the Master finds Will's meticulous diary, Will kills him to maintain the secret. With the timely assistance of Beanpole, who has been waiting outside the Tripod colony, Will escapes, and they return to the White Mountains.
The title refers to the gold colour prevalent in the Masters' cities, as well as the leaden weight of the increased gravity on the human slaves.
Will and Fritz travel to Eastern Europe, the Caucasus and the Middle East and set up resistance cells with young boys who question the power of the Tripods. The resistance, having ambushed a Tripod, discover that alcohol has a strong soporific effect on the Masters, and use this knowledge to simultaneously attack their cities. Will is one of the leaders of the attack on the European city. Having introduced alcohol into the aliens' city water systems, two raiding groups kill the resident aliens, but the initial attack on the last city is unsuccessful and an aerial attack is undertaken. While trying again to destroy the city with their rediscovered bombs, Henry dies in victory by destroying the 'city of gold and lead'.
The world is liberated from the Masters' thought control, and technology is rediscovered rapidly. The Masters' spaceship arrives, and they destroy the remains of the cities, presumably to prevent the humans from reverse engineering the Masters' technology and launching a retaliatory expedition. Humanity is saved, but the saga ends with a renewal of nationalist sentiments, with tensions building up towards war. The reader is invited by Will's musings to wonder: having mastered the Masters, can people master themselves?
The title of the book refers to the mysterious power source of the Masters' cities, which is a crucial element in the attack on the first city.
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 until the capped individuals are in control in most places.
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 held out against the initial invasion but is eventually invaded by France and Germany, now under the subjugation of the Masters. As the Swiss are themselves enslaved, the narrator and his family flee into the Alps, where they establish the "White Mountains" resistance movement that features heavily in the original trilogy.
- Hamish Hamilton (UK First Edition)
- Simon & Schuster (USA First Edition)
- Collier Books
- E. P. Dutton
- Thorndike Press
- Knight Books
- Turtleback Books
- Beaver Books
The series has been translated into Finnish, French, German, Hebrew, Persian, Spanish, and Mandarin Chinese (Taiwan).