Bruno is a nine-year old boy who is growing up in Berlin during World War II. He lives in a 5-story house with his parents, his 12 year old sister Gretel and a few servants. His father has a very important job and they have just been visited by a man called the 'Fury' (aka Hitler). After he visits, his father gets a new uniform and his title is changed to 'Commandant', and to Bruno's displeasure the family has to move away to a place called Out-With (Auschwitz).
When Bruno gets there he is immediately homesick after leaving behind his home, grandparents, and his three best friends. He is unhappy with his new home. It only has three floors and there are always soldiers going in and out the house as it belonged to them. Bruno is lonely and has no one to talk to or play with. However, one day while Bruno is looking out of his window he notices a bunch of people all wearing the same striped pajamas and that they are all living behind a big fence next to his house and garden. As he is a curious child, Bruno asks his father who these people are, but gets a rather unusual answer. His father tells him that these people are not people at all.
Due to sheer curiosity and boredom, he is soon willing to explore the house and its surroundings. As he walks the fence he spots a dot in the distance on the other side and as he gets closer, he discover that this dot is actually a boy. Excited by the prospect of a friend, Bruno introduces himself. The Jewish boy's name is Shmuel. Almost every day now, they meet at the same spot and talk. Eventually, for a variety of reasons, Bruno decides to climb under the fence and explore Shmuel's world.
The story ends with Bruno being about to go back to Berlin with his mother and sister on the orders of his father. As a final adventure, he agrees to dress in a set of striped pajamas and enters the other side of the fence to help Shmuel find his father, who went missing in the camp. The boys are unable to find him, and just as it starts to rain and get dark, Bruno decides he would like to go home, but they are rounded up in a crowd of people by the Nazi guards who start them on a march. Neither boy knows where this march will lead. However, they are soon crowded into a gas chamber, which Bruno assumes is a place to keep them dry from the rain until it stops. The author leaves the story with Bruno pondering, yet unafraid, in the dark holding hands with Shmuel. "...Despite the chaos that followed, Bruno found that he was still holding Shmuel's hand in his own and nothing in the world would have persuaded him to let go".
In an epilogue, Bruno's family spend several months at their home trying to find Bruno, before his mother and Gretel return to Berlin, only to discover he is not there as they had expected. A year afterwards, his father returns to the spot where the soldiers found Bruno's clothes (the same spot Bruno spent the last year of his life) and, after a brief inspection, discovers that the fence is not properly attached at the base and can form a gap big enough for a boy of Bruno's size to fit through. Using this information, his father eventually pieces together that they gassed Bruno to death. Several months later, the Red Army arrives to liberate the camp and orders Bruno's father to go with them. He goes without complaint, because "he didn't really mind what they did to him
Source: Wikipedia, backed up with my own knowledge of the book.
Bruno is a normal 9 year old boy who lives in Berlin with his parents and his sister, Gretel. Bruno lives in a wondrous 5 level house and likes his home, but he soon finds out he will be leaving soon.
His father was a soldier and due to current position, they had to move to a new house one that is big, and only has 3 levels, and Gretel says its name is out-with. Bruno's father was a large powerful man. He even had a certain phrase he would say when greeting or dismissing someone. Bruno wasn't sure what the words meant; all he knew was that all of Father's soldier friends had to say it to him, as well as Bruno, Mother, and Gretel. Those 2 words are,' ' Hail, Hitler!'. Bruno quickly decides he doesn’t like his new home. There are no other boys on the street to play with, actually no children at all! Until he decides to look around. Until he finds the fence. Until he finds Shmuel, the boy in the striped pajamas.