With a trove of gripping footage filmed by protestors, this documentary goes inside the uprising that rocked Iran after the death of a young woman in police custody — and sheds new light on a regime under unprecedented pressure.

Last fall, anti-government protests swept across Iran after the death in police custody of a young woman, Mahsa Zhina Amini, who was accused of not adhering to the Islamic regime’s strict dress code. In the crackdown on protests that followed, human rights groups estimate that more than 500 Iranians have been killed, including 72 children.

In a country where journalists are tightly controlled, young Iranians have been filming the uprising themselves and posting the videos online. For more than six months, FRONTLINE has been gathering and reviewing over 100 hours of this footage, cross-checking it with testimony from eyewitnesses and protestors, and following activists and exiles who have been gathering evidence of human rights violations.