Livonia, 1813: a decorated nobleman married to a peasant's daughter dares to tell Czar Alexander I the truth about his tyranny—and pays for it with imprisonment, then house arrest under constant watch. His brother-in-law secretly chronicles it all, unsure if the baron's madness is real or his last defense.
Under absolute rule, a man who acts wholly on his principles can look insane to everyone around him. Calling him mad gives power a convenient way to dismiss him, and he may also use the label as cover, saying as apparent gibberish what is too dangerous to say plainly. Those watching can never be sure which it is.
A ruler may ask a close friend to always tell him the truth, then find he cannot bear hearing it. Keeping that promise fully, by naming the ruler's own failures of leadership, can turn a trusted favourite into a prisoner held at the ruler's pleasure.
Fleeing abroad can amount to surrender, a choice suited to people who want revenge rather than change. Remaining where the rulers are forced to keep dealing with you makes you a stubborn, unwelcome presence, "an iron nail in the flesh" of the empire.
Under an absolute ruler, even someone who is only watching a dissenter has to hide his diary and quietly plan an escape. He also keeps wondering what is really true, because the arbitrary power behind the story could belong to any absolutist regime, in any era.