In 2013, filmmaker Poitras starts receiving encrypted emails from an anonymous sender called “CitizenFour”. Five months later she travels to Hong Kong with journalists Greenwald and MacAskill and meets clandestinely with this person, who turns out to be Edward Snowden, an NSA contractor. Snowden makes some explosive and far-reaching allegations about an NSA global surveillance program, and presents highly classified material as evidence. A media sensation ensues when the reporters file the story. The director later follows Snowden to Moscow, where he seeks asylum after the United States charges him with treason and theft of government property.

Unfurling like a thrilling detective tale, this riveting film probes the secrecy and complexity of our post 9/11 world. Poitras contrasts sequences of Snowden disclosing details of the program with footage of NSA officials lying to Congress about the extent of their surveillance operations. But beyond exposing governmental duplicity, she limns the murky area between national security and personal privacy, exploring the disturbing implications of an Orwellian state. Whether you consider Snowden a hero or a traitor, this Oscar-winning documentary warrants your full attention.