In the not-too-distant future, the world is ravaged by brutal climate changes, colloquially known as the Cloud Fall. The combination of pollution and relentless mining of Earth's resources through industrialism has left the environment nearly unlivable and extremely hostile to human habitation. Humanity is forcefully reverted to a simpler lifestyle, relying on barter for the two most valuable resources now: Water purifiers, called tabs, and silver, ground up to line the interior of breathing masks, to keep out a painful and fatal airborne disease known as Black Lung.