The film challenges many of the commonly held assumptions about our water systems and how people think about water. Its goal is to bust the global sense of impending doom by painting an alternative, optimistic water future and mapping out the ways to get there. The filmmakers believe that even one person with enough knowledge can make a difference and inspire a movement. The film tries to provide that knowledge and to envision a day when everybody has access to clean water and sanitation and in our lifetime.
Narrated by Liam Neeson, featuring Matt Damon and Jaden Smith, 'Brave Blue World' paints an optimistic picture of how humanity is adopting new technologies and innovations to re-think how water is managed.

In this programme, Mary descends into the city streets to discover the dirt, crime, sex and slum conditions in the world's first high-rise city. This Rome is not the marble Rome we know, but a vast, messy metropolis with little urban planning, where most Romans lived in high-rise apartment blocks with little space, light, or even sanitation. Forced outdoors into the city streets, she reveals where they went to hang out, get drunk, have sex and get clean. She looks at the Forum as a place of gamblers, dentists and thieves, and she explores the lustiness of Roman bar life and jokes. Finally, exploring law and order from the bottom up, Mary examines how this city really worked. She meets Ancarenus Nothus, an apartment dweller who lived in fear of the rent collector; Notorious Primus, who wrote about his three great pleasures in life - baths, wine and sex; and Unlucky Doris, a seven-year-old girl killed in one of Rome's many fires.