Stepniak’s note, we learn, was written in blood—a detail that likely awakened the letter burner’s sympathy and compelled him, in a courageous (and possibly final) act of defiance, to smuggle the missive out. Kornev’s visit to the prison is another bit of bravery, born of a newcomer’s naïve belief in the system; he was, we learn, appointed a prosecutor only three months earlier. (“Do you know where your predecessor is now?” someone asks, ominously.) In pursuing an audience with Stepniak, Kornev is taking on not only the prison authorities but also Stalin’s secret police, the N.K.V.D. For the next several hours—the film, though extraordinarily rigorous, is not bound by the strictures of real time—Kornev’s persistence will be met with deflections, delays, and excuses. Such a visit requires official permission, he’s told; the prisoner is ill and contagious. “Don’t forget about the risk of infection,” the prison governor says, and there’s more menace than concern in his warning; he’s referring to an ideological contaminant, not a physical one.