What happens to the food we digest after it leaves our bodies? Is it waste to be discarded or a resource to be reused? Looking for answers, director Rubén Abruña embarks on an investigative and entertaining quest through 16 cities across 4 continents. He follows the poop trail from the long Parisian sewers to a huge wastewater treatment plant in Chicago. 

The presumed solution to use the semi-solid remains of the treatment process as a fertilizer proves to be a living nightmare, because they contain heavy metals and toxic PFAS chemicals. 

Can excreta be used to grow food and ease the imminent fertilizer scarcity? He meets the Poop Pirates from Uganda who through work and songs teach people how to turn feces into safe fertilizer. In rural Sweden, an engineer shows him a dry toilet that makes fertilizer from urine. 
In Hamburg and Geneva, he discovers residential complexes with localized treatment plants, not connected to sewers, that produce electricity and fertilizer from human excrements. In the end, the director finds answers to sustainably reuse human poop and pee that also increase global food security, environmental protection, and hygiene and mitigate climate change.