"Stranger Things" Season 4 is going back in time to reveal Chief Jim Hopper's backstory and it may include some action-packed "Indiana Jones" style adventures.

David Harbour, who plays Jim Hopper in the Netflix show, teased what fans can expect with the upcoming season in a recent interview. Outside of the usual scary and terrifying monsters, he said that there will also be loads of action and adventure.

"It's very epic. There are monsters and horror and scares. There's also some great Indiana Jones-type action," Harbour told Deadline.

The promotional teaser for "Stranger Things" Season 4 shows Hopper in Russia as a prisoner. The details as to how and why he ended up there remain popular subjects of theories among fans. One suggests that he teleported to the country through the crack to the Upside Down during the explosion at Starcourt Mall. Another theory says that Russian soldiers captured him on his way out to find an escape out of the explosion.

Fans believe that a rescue mission will unfold in the upcoming season, which will then take the gang outside of Hawkins and to Russia. This would explain the season's tag line "We're Not In Hawkins Anymore." As with any rescue mission, planning, action, and danger are always involved.

Harbour's tease of "Indiana Jones" style action in "Stranger Things" Season 4 could pertain to Hopper's rescue. If not, then it could involve the character's backstory. The actor has confirmed that the instalment will reveal more about Hopper's story especially concerning those teased in the boxes in Season 2.

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Fans may remember the boxes labelled with "Dad," "Vietnam," and "New York" stored in the basement of Hopper's cabin. Eleven saw them but did not know what they meant. The upcoming season will dig into the meaning behind those boxes.

"Each season we see a different side of him. Last season was... a bit wackier, and I loved playing that. Now [in Season 4] he is painted in a bit of a darker palette; he's able to express some of these really deep things that we've... hinted at with the boxes in Season 2," he teased.

Harbour said he is "really excited to let people see these really deep colours" in Hopper. He said those boxes will reveal "Hopper's deep backstory." Perhaps fans will see the "Indiana Jones" type action scenes in "Stranger Things" Season 4 in a flashback sequence involving any of those boxes.

David Harbour in Stranger Things
David Harbour plays Chief Jim Hopper in the Netflix show "Stranger Things." Netflix / YouTube