In 2017, Philadelphia had one of the highest incarceration rates of any major city in the United States. And it’s become the epicenter of a historic experiment that could shape the future of prosecution in America for decades to come. When civil rights attorney Larry Krasner mounted a longshot campaign to become District Attorney—and won—he pledged to end mass incarceration by changing the culture of the criminal justice system from within. With unprecedented access to Krasner’s office, Philly DA explores the most pressing social issues of our time—police brutality, the opioid crisis, gun violence, and mass incarceration—through the lens of one man attempting fundamental overhaul from within the system.