The Boy in The Striped Pajamas by John Boyne follows Bruno's journey from his home in Berlin as the son of a Nazi Commandant, to his decision to accompany Shmuel, a Jewish inmate of Auschwitz, by going to the other side of the fence where he and Shmuel will stand together when they die in the gas chamber at what Bruno mispronounces as "Out-With."
The story starts in Berlin where Bruno has a seemingly idyllic childhood but is very aware of the boundaries set by his father. Bruno's father is an important man in the "Fury's" army and even though Bruno does not understand the significance of the move or the life-changing effects it will have on him, he does know that he must never defy his father. However after they have moved, Bruno becomes increasingly bored with the restrictions and decides to "explore" the fence and the curious people in striped pajamas which he has only previously seen from his window.
Bruno finds Shmuel sitting by the fence and the boys become friends. Bruno does not understand life on Shmuel's side of the fence and has an idealized image of what he think exists there. After more than a year of being friends Bruno will be returning to Berlin so he and Shmuel must say goodbye. They decide that Bruno should sneak under the fence so that he can see what it is like and also help Shmuel find his missing father. He will dress in pajamas like Shmuel's because then, apart from being a little "fatter," he will almost look like any of the other boys there. The fact that Bruno's father shaved his head because of a lice outbreak ensures that Bruno blends in with his friend.
Bruno is shocked and disappointed by what he sees on Shmuel's side of the fence. There are no cafes and shops and the children are not playing all the games he expected. They have no success finding Shmuel's father and so Bruno decides it is time to return home. However he and Shmuel are ushered along with many others into a sealed room where Bruno thinks they are taking shelter from the rain. He is anxious which is evident as he holds hands with Shmuel but has no idea what is about to happen as everything goes dark and Bruno is never heard of again.
Although it is never explicitly stated, the plot is resolved at that very moment when the lights go out and Bruno's story is effectively told. The novel concludes with the family's frantic but unsuccessful search for Bruno. Gretel, who is Bruno's sister, cries for her loss, his mother waits for him and then returns to Berlin in case he somehow found his way home, and even Bruno's father "didn't really mind what they did to him anymore" because he has lost all hope.