What is the main conflict in The Innocent by Ian McEwan?

The Innocent, a blend of coming of age narrative and espionage thriller, tells the story of Leonard Marnham, a young British postal worker and unexpected government agent in Berlin in the months following the end of World War II. As he finds himself caught up in a web of tensions spun between the American and British allies, he also discovers the joys of love and sexuality, with the two aspects of his life coming together in a horrific and intense climax. Both these narrative lines are, on some level, defined by the narrative's examination of the complex relationships between conquered and conqueror.