Conventional wisdom has it that the prospect of nuclear war subsided with the end of the Cold War and the collapse of the Soviet Union, but filmmaker Lucy Walker illustrates how the nuclear threat has only grown in unexpected ways and moved in new directions in this documentary. There are 23,000 nuclear weapons in the world today, a number of which are unaccounted for (when the USSR split into a handful of separate states, some of their bombs went missing), and as the technology becomes simpler, several major radical terrorist groups and politically unstable nations are trying to obtain nuclear weapons, a prospect that isn't as unlikely as one would hope. And what would happen if the wrong people got their hands on the bomb -- or if some of the "good" people were to detonate one through error or mistaken judgment? In Countdown to Zero, a number of leading politicians and political analysts -- including Jimmy Carter, Tony Blair, Valerie Plame Wilson, Mikhail Gorbachev, and Zbigniew Brzezinski -- discuss the question of nuclear war in the 21st century and what can be done to eliminate the weapons once and for all.