[1] The story begins during the Cuban Missile Crisis of 1962, with the majority of the narrative and gameplay taking place in an alternate, modern-day Soviet Union after a nuclear war.
[3][4][5] The artistic style of Nuclear Union was a dark retrofuturist one, with post-apocalyptic landscapes and older prototypes beside modern weapons, reminiscent of other famous Ukrainian games such as S.T.A.L.K.E.R.
Fifty years after the war, the fragments of the Soviet Union that were hastily brought underground have gradually become a real state with its own capital, a city called Pobedograd.
[6] The game's main protagonist is a former pilot of the Soviet military aviation, who is sent from the underground city of "Pobedograd" in the subsoil of Moscow to the radioactive external surface, for various missions on behalf of the underground government of Pobedograd, including the recovery of advanced Soviet pre-nuclear war technologies and investigating a set of strange and mysterious phenomena that are happening on the outer surface.
[7][8] According to in-game lore, the Korobov was revived when counter-revolutionary gangs found the documentation and the weapon began appearing in the regions of Ryazan and Tambov; the deficiencies of the weapon were corrected with it being referred to as "Object 93" (Ob'yekt 93) in reference to the year its schematics were discovered.