What is the conflict in The Boy in the Striped Pajamas?

The novel's main conflict involves Bruno and his relationship with Shmuel. Although, Bruno is unaware of the differences between them or the reason why Shmuel is kept on the other side of the fence, Bruno doesn't understand and is afraid of the way Shmuel is treated by others. For example, when Kotler abuses Shmuel, Bruno stays quiet. He doesn't stick up for his friend. Bruno knows he didn't respond like a true friend and promises Shmuel he won't leave him. He proves this in the end of their story by staying by Shmuel's side, as he unknowingly walks to his death.