In Siberia, a Soviet Commissar is murdered while investigating the death of a soon-to-be-exiled dissident's daughter. So Inspector Porfiry Petrovich (like the inspector from Crime & Punishment) Rostnikov is sent to investigate the Commissar's death. But only the Commissar's death. He's accompanied by a subordinate, the taciturn and unsettling Emil Karpo, and a man named Sokolov from the Procurer's office, ostensibly there to learn investigative techniques.
I wouldn't say Cold Red Sunrise is much of a mystery. Most of the evidence Rostnikov uses to draw his conclusions is kept hidden from us, relayed to him through whispered conversations or observations the narration does not see fit to let us in on. It can almost make an odd sense; this is Soviet Russia, where you had to be very cautious as to what conclusions you drew, or what truths you uncovered, and especially who you revealed them to. Why should the audience be trusted? Not that Rostnikov ever addresses us directly, it's not that sort of book. More that a society that can regard individualism with suspicion would necessitate keeping one's cards close to their vest.
I'm not even sure the book is meant to be much of a mystery. One thing I didn't realize until I'd finished it was this is one in a series of books Kaminsky's written with these characters. The 5th, to be exact. My guess is the stories are more about the characters and their lives in a Soviet Union that was starting to become more concerned with maintaining positive relations with the West (Gorbachev and glasnost get a few mentions). Which would explain Kaminsky devoting part of the book to Rostnikov's other subordinate, Sasha and his family life. There's also what seems to be a long-running plot thread about some headaches Rostnikov's wife is experiencing, and their concerns about their son Josef, fighting in Afghanistan.
'The place, even the wooden chuch building where no services were held, were part of a useless past that would no simply die. The entire town had no reasonable function for existing other than the weather station. Well, there was another reasonable function: to isolate people like Samsonov. Siberia was dotted with exile towns to receive those who, for various reasons, the State did not want to put into the more formal prisons farther east. One cannot be a martyr if he or she lives to a ripe old age.'