i haven't seen the movie, but i read the book. highlight:
the family is planning on returning to berlin and the boy went back to the fence, to meet his friend. the friend gave him the "pajamas" and he changed, and crawled under the fence. the boys were walking around, and the Nazis rounded them up. the boy didn't know where the march lead, and he thought they were just being taken out of the rain. they were lead into a gas chamber, and the boys were killed.