The movie is set in the fall of 1989, with tensions rising within the German Democratic Republic. A GDR border guard notices an escape attempt across the Berlin Wall and is faced with the decision of whether to fire or not on the fleeing citizen. The escapee reaches West Berlin as the guard begins shooting. He hits the escapee and several Western citizens, causing a nearby police officer to return fire. This incident causes severe tensions between the GDR and the FRG.
Meanwhile, Mikhail Gorbachev's plane fails to arrive safely in Moscow, and the Soviet Union's leader is presumed dead, allowing hardliners to seize power. As civil unrest in the GDR reaches a critical level, the new Soviet leadership decides to suppress it with force. The NATO high command notices the mobilization of GDR troops and the redeployment of other Warsaw Pact forces. Fearing an impeding attack on West Berlin or all of West Germany, it also mobilizes and readies its nuclear arsenal. This further escalates the situation, and East German commanders determine that it is imperative in light of the expected NATO attack to seize control of West Berlin. The attack causes a full force counterstrike by NATO forces, which quickly overwhelm East German defenders.
Soviet surveillance systems detect unverified ICBM launches (as they were prone to in reality) but due to the escalated situation the new leader, fearing the worst, decides not to wait for additional verification. The movie ends with a mock live report in front of the White House with air raid sirens heard in the background. The frantic journalist reports rumors of a Soviet attack and of a nuclear counterstrike authorized by the President of the United States. Video and audio is cut in mid-sentence, leaving only the snow of a lost signal onscreen.