WARNING: The following article contains spoilers for Stranger Things Season 3, streaming now on Netflix.
One of Stranger Things Season 3's biggest and most heartbreaking moments comes when Chief Hopper (David Harbour) gets caught on the wrong side of the platform when Joyce Byers (Winona Ryder) has to turn the keys to close the Russian rift to the Upside Down. Hopper appears to die, further supported by the finale in which Eleven (Millie Bobby Brown) moves away with Joyce. However, a Reddit theory suggests Hopper may still be alive and his return could be foreshadowed by a letter he wrote to Eleven, which she read just before departing Hawkins, Indiana.
Earlier in the season, Hopper goes from begging Eleven to demanding she leave her bedroom door three inches open when Mike (Finn Wolfhard) visits. Hopper's demeanour leads to a rift between himself and Eleven, who wants to enjoy the freedom of an average teenage daughter. Joyce recommends Hopper speak to his daughter in a heart-to-heart, but he instead ends up intimidating Mike in an ill-advised move that leads to the boy avoiding Eleven afterwards.
After the big finale, though, when Joyce shows Eleven the letter Hopper wrote to her when they pack up to leave, there's a clue in it that could be the key to his salvation. After explaining to her how much he loves her and that she is indeed a daughter to him, he ends: "But, please, if you don't mind, for the sake of your poor old dad, keep the door open three inches." Now, it seems like a nod to him making sure El and Mike weren't getting too hot and heavy in her room, but some fans believe the Duffer brothers are referencing an arc to come involving the Upside Down and Hopper's return.
As we never saw his body after the reactor beneath Starcourt Mall exploded, Hopper may actually be trapped in the Upside Down. Fans believe he may have run away from the reactor's explosion and possibly jumped, or been sucked into the rift as Joyce closed it -- something she wouldn't have seen as the reactor's energy produced a blinding light. As for the door in the letter, they think it's the rift Eleven will now have to open to retrieve Hopper.
It definitely flips the script, as the show's been about closing the doorway since Season 2, but it does harken back to Season 1 when Hopper and Joyce ventured into the dark dimension to retrieve Will Byers (Noah Schnapp). It could be that Hopper, the man who rescues everyone, is now in need of a search party to come save him, and who better than the girl the Mind Flayer fears most.
An interesting point has also been brought up in regards to investigative reporter Murray (Brett Gelman), as his number was given out by Joyce to the government officials who initially oversaw the Hawkins lab and the rift. When fans call it, they get a couple of voicemails, including one with Murray telling Joyce he needs to speak to her about something important. It may be he's found a clue that Hopper's alive, especially if Hop has his radio. Murray may be tuned in using his own devices to scour for signs of survival after Season 3.
Doubters have pointed out, though, Hop might well be the "American" the Russians are holding in their lab in Kamchatka, so if that's the case, Eleven and her friends would have to go to Russia, not the Upside Down. However, some argue our heroes might use the Upside Down as a means of getting to Kamchatka directly, as the Russians are clearly still operating their own rift. In other words, it becomes a passageway between two countries, providing scary terrain to navigate. Plus, how else would they find or gain access to the wintery Soviet base?
Ultimately, speculation will keep mounting, especially with such an ambiguous ending. Eleven can't sense Hopper's presence as she doesn't have her abilities, so for all intents and purposes, everyone assumes he's dead. It would be very surprising if this death sticks but the Duffer brothers could simply be showing fans how high-stakes these adventures get despite the laughs and campy 80's feel. But, as usual, there'll be optimists who think it's way too early to kill off such a pivotal character with so much story to tell.
Folks still want to see Hopper and Eleven having a happy father-daughter relationship, as well as him finally getting that date with Joyce. Well, until Season 4 details emerge, all we can do is hope El gets her powers back to crack the rift and track him using the letter as a totem. And more so, hope that whether Hop's in the Upside Down or the Russian prison, he's still alive and kicking, and not being used as food for a Demodog.
Created by the Duffer Brothers, Stranger Things stars Winona Ryder, David Harbour, Finn Wolfhard, Millie Bobby Brown, Gaten Matarazzo, Caleb McLaughlin, Noah Schnapp, Natalia Dyer, Charlie Heaton, Joe Keery, Priah Ferguson, Cary Elwes, Jake Busey and Maya Thurman-Hawke.