One such is Korolev, a former soldier in the Russian Army who fought against the Germans in World War I, the Czarist forces in Russia's own civil war, and then the invading Poles. He is fundamentally a thoroughly decent man, straightforward and steadfast, who sees himself as a loyal Soviet citizen. He believes that the sufferings of the present will bring about a better future so long as the advances are not undone by the machinations of traitors, spies and saboteurs abroad and at home. But he is also aware that one false step, one word spoken, even in jest, out of turn, could result in disaster for him, his family, his colleagues and his friends. Anyone, no matter how eminent, even the feared Yagoda, General Kommissar of State Security, can be denounced for little or even no reason and then disappear into the Lubianka or the gulags as had also happened to a colleague of Korolev's who had made an unwise joke about the NKVD (the department responsible for state security). This atmosphere of perpetual fear and paranoia forms the overarching theme of all three novels manifested in the sinister power of the NKVD which is a continuing presence in all three novels as is the criminality and corruption of the state authorities.
Korolev is divorced and his ex-wife Zhenia and his son Yuri live some distance from Moscow. Given the appalling housing conditions in Moscow, Korolev is lucky to have a room in a flat occupied by the widow Valentina Koltsova and her daughter Natasha. Korolev's developing feelings for Valentina are one of the many strands in these novels as is his attachment to Russian Orthodox Christianity; he still has his mother's Bible which would be enough if discovered to render him liable to denunciation and deportation to the gulags.
Another theme is Korolev's strange relationship with Count Kolya of the Moscow Thieves, brought about by his friend and neighbour, the (real-life) Isaac Babel. The Thieves were a criminal organisation, which really existed (and still do today, according to on-line sources, in the shape of the Russian Mafia). They controlled the Russian underworld. They see themselves as being in perpetual opposition to any government or law enforcement agency with their own strict rules, ruthlessly enforced. Kolya supplies Korolev with information he would not have been able to gain otherwise. Similarly, Korolev is aided by his acquaintanceship with a gang of street children, orphans (often the children of those so-called Enemies of the People who had disappeared into the gulags) abandoned by the State to fend for themselves on the streets of Moscow