When an American mom discovers an SOS note stashed in a package from Kmart, she never imagines it will lead to the closure of Masanjia, China's most notorious labor camp. When news of the note goes viral, the writer, a Chinese engineer who had been jailed for his spiritual beliefs, fears for his life and his family's safety. Realizing the spotlight is a chance to further expose the brutality of the Chinese regime, he decides to make a film about the harsh reality of being a human rights defender in China, risking his life in the process. For over a year, Sun Yi, the SOS writer, details his entire story on film as he revisits his torturous past at Masanjia and is hotly pursued by authorities. Secret-camera footage and harrowing glimpses of his personal life offer a rare look inside China's terrifying police state through the lens of a political dissident, showing us a true modern hero who will stop at nothing to expose the truth.