Joseph Stalin spends the war years playing both sides of a shifting alliance, and this six-part series uses declassified Soviet archives, opened only after 1991, to show how. Newly released transcripts, secret police files, and diplomatic cables sit alongside interviews and archival footage tracing the deals struck away from the public record: the Nazi-Soviet Pact that carved up Poland, the uneasy wartime partnership with Churchill and Roosevelt once Hitler invaded the USSR, and the horse-trading over Eastern Europe that set the terms of the Cold War before Berlin had even fallen. The series treats Stalin as a calculating operator rather than a wartime footnote, weighing his willingness to sacrifice millions of Soviet lives against his skill at extracting concessions from allies who distrusted him as much as they needed him. Six episodes move chronologically from the pact with Hitler to the postwar carve-up, using the newly available documents to argue that the war's real turning points were negotiated in private rooms, not on battlefields.