Grigori Rasputin dies in December 1916, and the official story, poison, gunfire, and drowning at the hands of aristocrats led by Prince Felix Yusupov, has stood for a century. This BBC Timewatch investigation puts that account under a magnifying glass, literally, as former Metropolitan Police Commander Richard Cullen re-examines the original autopsy photographs and finds wounds that do not match the confessed killers' stories. Intelligence historian Andrew Cook builds a different case: that British intelligence, worried Rasputin might pull Russia out of the war, had its own man in the room that night, agent Oswald Rayner, and that the fatal shot was his. The film moves between the Yusupov palace where the killing took place, the forensic evidence Cullen picks apart frame by frame, and the wartime politics that gave a foreign intelligence service a motive. Tsar Nicholas II and Tsarina Alexandra's dependence on Rasputin sits behind all of it as the reason anyone wanted him dead in the first place. Cook and Cullen do not agree on every detail, and the film lets that disagreement stand.