The notion was improbable. Even if it lacked direct examples of provocation, the things unmentioned in a diary were just as important as the things that were written down. Deciding to offer these wisdoms to his trainee, Leo stood up.

—Let me tell you a story. A young man once remarked in his diary that on this day he felt inexplicably sad. The entry was dated 23 August. The year was 1949. What would you make of that?

Grigori shrugged.

—Not much.

Leo pounced on the claim.

—What was the date of the Non-Aggression Pact between Nazi Germany and Soviet Russia?

—August 1939.

—The 23rd of August 1939. Which means this man was feeling inexplicable sadness on the tenth anniversary of that treaty. Taken together with an absence of any praise for the soldiers who defeated Fascism, for Stalin’s military prowess, this man’s sadness was interpreted as an inappropriate critique of our foreign policy. Why dwell on mistakes and not express feelings of pride? Do you understand?

—Maybe it had nothing to do the treaty. We all have days where we feel sad or lonely or melancholy. We don’t check the historical calendar every time we feel such things.

Leo became annoyed.

—Maybe it had nothing to do with the treaty? Maybe there are no enemies? Maybe everyone loves the State? Maybe there are no people who wish to undermine our work? Our job is to reveal guilt, not naively hope that it doesn’t exist.

Grigori considered, noting Leo’s anger. With unusual diplomacy, he modulated his response, no longer as confrontational but sticking by his conclusion:

—In Polina’s diary there are mundane observations about her daily routine. As far as my abilities allow I can see no case against her. Those are my findings.