Part 1 shows how the Berlin Wall was built in a clandestine operation that surprised even the Allies in West Berlin. It was a time of families torn apart, of desperate East Berliners leaping from their apartment windows, of men and women digging tunnels to the Western sector. It was also the time when Berlin became a hotbed of international espionage, with Stasi, KGB, CIA, MI6 and BND all jostling for information in a city of threats and secrets. This film rebuilds the Wall with CGI and re-enacts the most daring escapes. Interviews with ex-border guards, spies, politicians, escapees and the engineers of the barrier are interspersed with archival footage, home movies and propaganda films.

Part 2 focuses on dramatic East Berlin escape stories of the 1970s and '80s as the GDR regime crumbled at the end of the Cold War. But as the GDR was planning a new, "gentler" Wall with infrared, laser, chemical and vibration detectors, U.S. President Reagan was exhorting the Soviet Union to "tear down this Wall"