Throughout the novel, Ian McEwan explores the dark interior of human nature in the decades following World War II. The character of Jeremy, who is both fascinated and repulsed by trying to make sense of what human beings are capable of, seeks answers in the stories of June and Bernard, the parents of his wife, Jenny. Both the personal relationship of this married couple and their involvement in Cold War-era Communism draw Jeremy to learn more about them.
Focusing on June to the point of obsession, he undertakes to write her biography. Through doing so, he learns the story of how two black dogs attacked her on the shore one day and she had to defend herself, using rocks and a knife to drive them away. His experiences of self-exploration intensify in the course of writing the book, as he becomes its subject as well as its author.
Jeremy’s travels with Jenny to Poland and with Bernard to Berlin provide two examples of his confronting the war’s legacy. The black dogs represent the Nazis who committed atrocities in the concentration camps. He finds that even during a liberating occasion, the fall of the Berlin Wall, humans’ capacity for violence is unescapable.