THE WHITE MOUNTAINS by John Christopher.
"The White Mountains" is a short narration about the adventures and misfortunes of a young teenager named Will Parker, who runs away from his home, trying to avoid became another mind-controlled servant of the Tripods. Tripods conquered the earth years ago. They are frightening machines with three long metallic legs; they use a mind control device called the Cap. At the age of 14, every man got his cap, becoming a very different person and a loyal servant of the Tripods; when fails, it destroys the mind of the capped man making him vagrants, a sort of crazy or dumb people, that can't do any productive task.
Will had two cousins, Jack -his best friend- and Henry, the most annoying and unbearable person that he ever knew. Jack was 14 and Henry was 13. When Jack got his cap, Will lost his best friend and started to doubt about his destiny. He met Ozymandias a vagrant that arrived to the town and become his friend. On Will's questions, he revealed him that far away, crossing the ocean, deep in the White Mountains of the Austrian Alps, a band of uncapped rebels are plotting to overthrow their captors. Those revelations shocked Will and made him decide to leave off his home to join them. Ozymandias gave Will a map and the directions to get there. However, when he's about to run away, Harry's mother pass away and his father decided to send the boy to Will's house, delaying his intentions; the night that Will departed was caught by Harry, for his surprise, Harry didn't alert Will's fathers but asked him to join the expedition. Will accept and told Harry everything about the White Mountains. They decided to walk by night and rest by day. After a few days, the two kids arrived to Rummey, a town with a port and they find Curtis, Captain of The Orion, one of the freemen; He took them to France: There, they met Jean Pierre, a French teenager who didn't want to be capped.