Warning: Major spoilers ahead for Stranger Things Season 3, so ~tread lightly~, my friends!
Okay, so the Season 3 finale left us with a few loose ends: Even though the Mind Flayer has been defeated and the Gate in Hawkins was closed, we know there is still (at least) one Demogorgon alive — and it's in Soviet Russia.
There are a bunch of theories on whether it's the same Demogorgan from Season 1 — and who "the American" prisoner briefly mentioned could be — but it sure looks like the battle between worlds isn't over, and the Soviet Union will continue to play a huge role in whatever happens next...
Which is why this theory from Reddit user Gamer_Nation, posted Tuesday night, makes SO. MUCH. SENSE.
The timing lines up: If we're due for a spring-themed season that takes place relatively soon after Season 3, then there's a VERY good chance Season 4 will overlap with the real-life explosion at the Chernobyl Nuclear Power Plant...
...which took place in Soviet Ukraine on April 26, 1986.