During WWII, before the Americans came in, the Nazis approached the English with the offer of peace -- the Nazis get to keep what they have and the English stick to their own island. In our timeline, Winston Churchill riled people up and they continued fighting. In Farthing, they took the deal. The story alternates chapters from Lucy Kahn, a rich girl in a political family who has married a Jew, and Inspector Carmichael, who investigates the murder. You see, Lucy's folks invited a lot of people, insisting on Lucy and her husband, to a party. And then the man who made peace gets killed and in a way that implies a Jew did it. The Inspector is pretty sure Lucy's husband didn't do it, but who did?
The following chapters, as we learn more about these folks and who they are, and watch the Inspector searching for the truth, become fraught with tension about truth, honesty, and justice. Politics lifts its heavy hand to become more rigid, more like the Nazis, and to make Lucy's husband be the killer. The Inspector is left with a difficult choice.
All of us enjoyed this, even if it wasn't SF, and most are continuing on to Ha'penny. It's a great book.