The twists in this story kept me going to the end. A man assigns an agent to a position in Berlin, and the agent disappears immediately. Smiley and co. investigate the disappearance. The story is from the point of view of Ned, the manager making the fatal assignment. He is new to the field and finds himself in the thick of it and under suspicion.
This is a short story taken from the collection The Secret Pilgrim. It is an audiobook read by John Le Carre.