In September 1961, UN secretary-general Dag Hammarskjöld's plane mysteriously and fatally crashed while flying over African soil. With Hammarskjöld on his way to mediate tensions and defend Congo's independence-contrary to the interests of Europe's mining corporations-the crash was thought by many to be an assassination. As Cold Case Hammarskjöld director Mads Brügger (The Red Chapel, The Ambassador) begins to investigate the case with fresh eyes over 50 years later, he uncovers a conspiracy more sinister than anything he'd initially imagined. Brügger leads viewers down a wild investigative rabbit hole, and after scores of false starts, dead ends, and elusive interviews, Brügger and his private investigator sidekick begin to uncover secrets that could upturn history. This thrilling documentary challenges expectations of the genre and calls the fundamental nature of truth into question.