The Forgotten Shadows (1970)

A french fan-film setting after the events of the series "Stranger Things" Season 3. Early Winter, 1985. Presumed dead by the world, Jim Hopper finds himself trapped in a secret Russian gulag, the Pot’ma Camp. Haunted by visions of his past, Hopper struggles to survive days after days in the Pot’ma camp. Until Dmitri Antonov, a guard also tormented by his own demons, offers him a chance to escape.