Dead Man's Letters (1986)

"Dead Man's Letters" is a 1986 Drama movie directed by Konstantin Lopushansky and starring by Rolan Bykov, Iosif Ryklin. In a world after the nuclear apocalypse a scholar helps a small group of children and adults survive, staying with them in the basement of the former museum of history. In his mind he writes letters to his son — though it is obvious that they will never be read.