It is August 1991, the USSR has only a few days left before its tremendous collapse and KGB officer Maksim Rukov has been moved, without explanation, to the newly formed Department P which investigates KGB corruption and roots out possible double-agents and traitors.

The game's interface and engine is based heavily on Cryo's previous game, Dune, using the same point-and-click system, and a pseudo first-person perspective. The game also allowed players to rewind to the beginning of chapters to correct mistakes they had made.

KGB was later re-released in an "enhanced" CD-ROM version featuring new video sections of actor Donald Sutherland as Rukov's father, giving hints and clues whenever needed. The game was also re-titled Conspiracy for this re-release.