Tucked away deep in the heart of Russia, there is a hidden city where thousands of men, women and children live and work behind barbed-wire fences monitored by armed guards. The residents are told they are the nuclear shield and saviors of the world. They are told that everyone on the outside is the enemy. One of the most contaminated places on earth, and home to Russia’s largest stockpile of fissile materials, this place is called City 40. In this feature-length documentary, the film crew gets smuggled inside City 40 and—behind a psychological facade of normality—they encounter a single mother and a handful of brave residents who risk their lives to expose human and environmental catastrophes that threaten the world.