'Stranger Things' Season 4: Everything the Cast Has Told Us About What's Next! (Exclusive)

WARNING: We're about to openly reference the biggest surprises, shocks and spoilers from 'Stranger Things' season three!

WARNING: We're about to openly reference the biggest surprises, shocks and spoilers from season three of Stranger Things! If you have not already binged the latest season, leave now!

After bingeing eight glorious and gut-wrenching episodes, season three of Stranger Things is officially over. 

We've already sobbed alongside David Harbour about Hopper's "stunning" finale fate, and obsessed over which American prisoner could be hiding in that mysterious post-credits scene, so it's time to focus on one very important thing… Stranger Things season four!

Although Netflix has yet to officially announce that the beloved drama series has been renewed for a fourth season, we'd be shocked if the Duffer Brothers didn't take us back into the Upside Down for at least one more adventurous season.

So in anticipation of the next possible chapter, ET caught up with David Harbour, Millie Bobby Brown, Winona Ryder and many more stars at the world premiere red carpet in Los Angeles last week to get the inside secrets on everything they know and all the things they're hoping to see in season four of Stranger Things!

David Harbour (Jim Hopper)

Following that shocking season three post-credits scene, we're currently praying to the Duffer Brothers that Hopper somehow survived that treacherous blast and could be the mysterious "American" prisoner that the Russian soldiers briefly refer to at the beginning of the bonus scene. 

And you know what? When we interviewed Harbour at the Stranger Things world premiere red carpet last week, the actor revealed that he's also crossing his fingers for a happy ending for Hopper.

"I have no idea!" he exclaimed when we pressed him about the unknown prisoner behind the door. "I mean that, of course, is my hope, too. It seems pretty crazy, though!" 

"That machine went off and blew up and Hopper seemed to be trapped there," Harbour explained. "He did glance around a little bit, but he seemed to be trapped and the machine exploded. And then you cut to... some town in Russia right? Where there’s some American and some prisoner. I don't know, I mean, it seems strange."

Harbour revealed that he knows "nothing" about season four because the Duffer Brothers have "dodging" him ever since they wrapped season three. 

"I know as much as you. I've seen the final episode -- it’s extraordinary, it’s magnificent. What Hopper does and what happens to him, he acts like the person he is meant to be. And then there is this mystery at the end," he continued. 'I don't really know what’s going to happen, but if you find out from the Duffer Brothers, let me know."

Winona Ryder (Joyce Byers)

After that "definitely emotional" season three finale and losing yet another love interest on the show, Ryder confessed that she’s rooting for Joyce's happiness next season. 

"Oh, gosh, I mean, I feel for her and I want her to find a sense of peace -- but also then there’s no show if she’s at peace," she said with a wry smile. 

And although the Golden Globe award-winning actress is not sure what’s next for Joyce, Jonathan, Will and Eleven in their new adventures together now that they've moved away from Hawkins, she does hope that there are many more group scenes together. 

"[I want] just more of her with the cast. It’s so fun to work with everybody and I feel so lucky," she shared.

Noah Schnapp (Will Byers)

"Oh, my God, the ending -- it was really sad. I mean, I cried," the 14-year-old actor admitted at the premiere. "I hope Hopper isn’t fully gone, but I feel like he’ll be coming back. I don't think he’s gone forever."

Following that hopeful note, Schnapp revealed that the Duffer Brothers have already told him quite a bit about Will's upcoming journey in season four. 

"I know that I might have a separate storyline from everyone else, so we might be filming, like, in another place," he said, referencing the Byers' decision to move away from Hawkins in the final scene of season three. "I hope he’s happy, but really, I love when he’s suffering because that’s fun to play."

(For the record: Schnapp was coy and quick to clam up when pressed him to spill about Will's new potential sibling dynamic with Eleven. "I don't know. I can’t say anything!" he teased. )

Charlie Heaton (Jonanthan Byers)

When we caught up with Heaton on the red carpet, Heaton divulged that the season three finale was a heartbreaking episode to watch – but it was even more difficult to film.

"The end, it was really sad to film. That was potentially the last time we’re going to be at the Byers' house," the English actor said. "The first shot I ever had was inside the Byers' house, so to kind of see it and pack it up and be over in that location, it was really sad and [full of] goodbyes because we’re splitting up. So, I really don’t have any idea where it will all be next year."

Heaton confessed that he rarely thinks about what's next for Jonathan because "the [Duffer] Brothers always come up with something so much better," but there is one thing he's hoping for in season four: "I’d like to have more of a relationship with Joyce this year," he said. "Because I think the relationship between Joyce and Jonathan has been lost for a moment, so it would be great to do a bit more with her." 

Natalia Dyer (Nancy Wheeler)

Following that "roller-coaster" finale, Dyer said that she's keeping her fingers crossed for Nancy to continue down her new journalistic journey in the next chapter. 

"I really trust those brothers to write something good. They come up with something better than I could ever imagine," the brunette beauty dished. "I just hope she continues on this path of really believing in herself and I love that this investigative -- almost Murray-inspired -- journey of hers."

"I just think it suits her and I think she’s really finding herself in it,' Dyer continued, "So I kind of hope she keeps going in that direction. It’s like, where could they possibly go? I have no idea, but they’ll figure it out and I hope that’s where she's going."

Finn Wolfhard (Mike Wheeler)

Wolfhard was quick to praise the Duffer Brothers for their "Avengers-type post-credits scene" when we caught up with him on the red carpet, and said that the finale was a "great ending" for the season. 

"It’s always like this every single season," he explained. "When you finish it and you read the last episode, you’re like, 'How are the Duffers going to get us out of this?' And they do every time, so I guess we’ll see what they have for next season."

Since Mike is currently heartbroken that Eleven and Will are moving away from Hawkins, Wolfhard is hoping that season four will bring a few more light-hearted moments to our screens. 

"I loved doing comedy and I loved putting Mike in awkward situations that he would normally not be in, because that’s the most fun thing to play," he later shared to our cameras on the red carpet. "And Mike when he’s flustered is really fun, so I definitely want to do more stuff with that."

Gaten Matarazzo (Dustin Henderson)

Following that "quite perfect" finale, Matarazzo revealed that he was excited to see the "amazing" post-credits scene that the Duffer Brothers decided to include at the very end of season three. 

"They’ve never really done anything like that before, so it was really exciting and I’m really excited to see where they go with that," he gushed.

As for his season four storyline? The 16-year-old is envisioning a brand-new type of adventure for Dustin. "It would be cool to see him have some kind of job. For so long, I’ve wanted to see him work at the Arcade -- at the Palace Arcade with Keith -- and have Keith be his boss,"  he revealed. "They have that rivalry and it’s hilarious and I want to work with Matty [Cardarople] more because he’s amazing."

When we mentioned that we definitely want more singing and Suzie in season four, Matarazzo was quick to agree. "I think we all do, we all definitely do," he said with a laugh.

Millie Bobby Brown (Eleven)

Brown was not able to share her knowledge or hopes for what's next for Eleven in season four, however, the 15-year-old actress did share a special message to the fans who have just finished bingeing season three.

 "We're really sorry that you're so sad, but we're happy because we did a good job!" She exclaimed to ET during a joint interview with Wolfhard and Schnapp at the Stranger Things junket in Los Angeles last week. "And please keep the door open three inches."