On April 12, Netflix dropped a full three-minute long trailer for Part One of Stranger Things 4. It was a lot. From the Underground in the Upside Down to Max at Billy’s graveside, there was so much to take in. Here are the big takeaways:

• The Byers/Hopper Family have been relocated to California by the U.S. government as part of witness protection.
• Eleven no longer has her powers. She is taken away, and it looks like it’s in a desperate effort to bring them back.
• Russia is having its own Upside Down issues.
• The Mind Flayer has a human body now.
• Journey has aged spectacularly well.

Netflix released the previous teaser on Stranger Things Day, on Nov. 6, 2021. The teaser picks up after Eleven and Will’s move to California at the end of Season 3, showing how Eleven hasn’t exactly had the best adjustment to her new school. In the clip, Eleven talks about looking forward to spring break, which immediately cuts to tons of explosions and chaos.

Before that, Netflix released a brief and cryptic sneak peek at Season 4 during its TUDUM event on Sept. 25, 2021. The creepy teaser is all about the mysterious Creel House. The haunted house was once owned by a seemingly picture-perfect family in the ‘50s, but the Stranger Things crew will explore it after it’s been abandoned for what looks to be decades.

Before the Creel House vid, an Aug. 6, 2021, “sneak peek” teaser with showed glimpses of a creepy clock, the gang investigating in a dark hallway, an amusement park, high school cheerleading, and Eleven (who has bangs now!) being held back by some men in black. The clip was the first confirmation that Season 4 will return in 2022.

Stranger Things previously released three teasers for Season 4, plus one "behind-the-scenes" glimpse:

The first came on Sept. 30, 2019, when Netflix announced an overarching deal with the Duffer Brothers. As part of that deal, Season 4 was a go. That said, there wasn't much in the way of details in the teaser.

The second one came on Feb. 14, 2020. Call it a love letter of sorts, the video clip showed fans that filming on the new season had begun. It also confirmed what most fans had guessed: Hopper was "The American," and life on the Kamchatka peninsula is rough.

Two weeks later, fans got a look at the cast coming together for the season's first table read. Note David Harbour's shaved head, indicating filming for his scenes had already begun.

After a long, pandemic-related delay, another Season 4 teaser turned up on May 6, 2021, called "Eleven, are you listening?" Is it a flashback? A dream? A nightmare? Or has Eleven been recaptured by her Papa now that Hopper is gone?

The first images for Stranger Things Season 4, Volume 1 arrived on March 23, 2022. They raised a lot of questions from the getgo. For example, what in heaven’s name is making Dustin scream at a Lite-Brite?

It’s good to see Robin got a new job, but holy blunt cut, what in heaven’s name happened to her hair?

Who told Eleven that those bangs were a good idea?

Who in the name of Dirty Dancing’s Jennifer Grey told Nancy that... any of that... was a good idea? (I am dying over the pink ruffles on Robin.)

At least we know who to blame for Season 4’s new dragon master Eddie Munson’s haircut: Every hair band on MTV.

It’s good that Joyce and Hopper are headed home to America. Hopefully, they’ll drive everyone to a Hair Cuttery when this is all over.

Who's Back:

Stranger Things has been slowly expanding the cast beyond the show's first season core of Finn Wolfhard, Gaten Matarazzo, and Caleb McLaughlin as Mike, Dustin, and Lucas. Millie Bobby Brown was supposed to only last one season as Eleven, but the writers changed their minds and kept her in the story. Noah Schnapp went from recurring actor to main cast member in Season 2 as Will Byers, which is when the show also added Sadie Sink as Max. All five stars are back for Season 4.

Also returning this season: Winona Ryder as Will's mom, Joyce Byers, and Charlie Heaton as her older son, Jonathan. Natalia Dyer will return as Mike's older sister, Nancy, and Cara Buono is back as their mom, Karen. Priah Ferguson was promoted to series regular for the new season, so she'll be back as Lucas' little sister, Erica. Brett Gelman also got the series-regular upgrade, so Murray Bauman will be back too.

Joe Keery and Maya Hawke are also returning as BFFs Steve Harrington and Robin Buckley. And of course, as mentioned above, David Harbour is back as Chief Hopper. And finally, in a surprise reveal, Matthew Modine returns for the first time since Season 1 as Dr. Brenner.

New Faces:

According to Deadline, new series regulars for Season 4 include Jamie Campbell Bower (Sweeney Todd), Eduardo Franco (Booksmart), and Joseph Quinn (Catherine the Great) who play Peter Ballard, Argyle, and Eddie Munson, respectively. Netflix added to that list on June 9, 2021, as part of "Geeked Week" with an announcement Amybeth McNulty, star of the streamer's recently canceled Anne With An E, will be joining the series as Vickie, a brand-new nerd for the gang and potential love interest.

Along with McNulty, Netflix revealed a few more new students fans will meet at Hawkins High, including Black Lightning's Myles Truitt as Hawkins basketball star, Patrick, The Village's Grace Van Dien as Chrissy, Hawkins High's lead cheerleader, and Regina Ting Chen (Queen of the South) will play Ms. Kelly, a popular guidance counselor.

Season 4 will also add Tom Wlaschiha (Jaqen H'ghar from Game of Thrones), who will play a Soviet soldier named Dmitri, with Nikola Djuricko as his fellow soldier, Yuri.

Horror icon Robert Englund (A Nightmare on Elm Street) will play a probable villain (or maybe just a misunderstood man) Victor Creel.

Other new faces will include Sherman Augustus (Lt. Colonel Sullivan), Mason Dye (Jason Carver), Logan Riley Bruner (Fred Benson), Logan Allen (Jake), Elodie Grace Orkin (Angela), John Reynolds (Officer Callahan), and Rob Morgan (Chief Powell).

On Feb. 17, 2022, Stranger Things released four new posters, each showing the different locations where the show will be set. The first teased the far reaches of Russia, showing Joyce and Hopper reunited, and Murray Bauman also along for the ride.

The caption released with it read: “001. Russia. Getting the band back together. Bring a jacket.”

“002. The Lab. Every story starts somewhere.”

This image goes along with the footage fans have already seen, of Eleven returning to the lab, though it’s still not clear how much of this is in her memories/dreams and how much is real.

“003. Creel House. Tick-tock.”

This is a big group. Down center we’ve got Max and Lucas, middle row are Steve, Dustin and Erica. In the top row, it looks like Nancy and Robin.

“004. California. Hold onto your butts, brochachos.”

And finally, California. Down front we have Mike and Will. Ahead of them, it looks like that could be Jonathan and perhaps a newcomer — possibly a friend the California crew meets after their move?

And here’s the full poster featuring all four locations.

Netflix shared a plot summary in February 2022:

It’s been six months since the Battle of Starcourt, which brought terror and destruction to Hawkins. Struggling with the aftermath, our group of friends are separated for the first time — and navigating the complexities of high school hasn't made things any easier. In this most vulnerable time, a new and horrifying supernatural threat surfaces, presenting a gruesome mystery that, if solved, might finally put an end to the horrors of the Upside Down.

Beyond that, fans don't have a lot of confirmed plot details other than Hopper being alive and in Russia. But based on the show's history, there are a few things fans can count on:

Stranger Things has been covering one season per year, which means Season 4 will likely take place in 1986. That gives a twist to Hopper's being in Russia. On Saturday, April 26, 1986, the No. 4 reactor at the Chernobyl Nuclear Power Plant melted down, and it was one of the biggest disasters in modern history. How that figures into the series (if at all) remains to be seen. Chernobyl is 4,541 miles from the Kamchatka peninsula, but that's real-world miles. As far as the Upside Down is concerned, it could be next door.

Speaking of Hopper, Harbour has given a few hints about what's to come. In an interview, he reminded fans of a scene in Season 2, in which Eleven finds boxes of Hopper's history labeled "Dad," "Vietnam," and "New York." Harbour promised those boxes are not a throwaway detail, although how Hopper's past will come into play is still a mystery.

Netflix unveiled the nine episode titles for Season 4 on Nov. 6, 2021. A couple stand out as referencing important characters, like “Dear Billy,” a nod to Max’s violent brother, and “Papa,” which is the name Eleven used for Dr. Brenner.

1. “The Hellfire Club”

2. “Vecna’s Curse”

3. “The Monster and The Superhero”

4. “Dear Billy”

5. “The Nina Project”

6. “The Dive”

7. “The Massacre At Hawkins Lab”

8. “Papa”

9. “The Piggyback”

Another note on the upcoming episodes: They’re going to be very long. In a May 18 interview with TheWrap, the Duffer Brothers teased that Episodes 7 and 9 in particular will feel more like movies due to their length.

You’re definitely going to want to clear your schedule for the Season 4 finale, because it’s apparently going to be longer than most movies. “We will say that it is over two hours,” Ross Duffer said of the upcoming finale. “It’s a big one.”

With little to go on, there aren't many theories so far. The premiere’s title, "The Hellfire Club," has some fans speculating about a comic book angle featuring the X-Men and perhaps a plotline involving mutant powers. But so far, there's nothing to prove it one way or the other.

The most prevalent theory revolves around Hopper and how his imprisonment in Russia will play out. Based on Harbour's mention of how his character takes a dark turn this time around, fans think he might be this season's villain. Could Russia send him home to act as a sleeper agent, Manchurian Candidate-style? Or could it be something worse?

On Feb. 17, after over two and a half years since Season 3’s debut, Netflix released a letter from the Duffer Brothers, addressed to fans. They called Season 4 “the most challenging of any previous season,” and also stated the new season is twice the length of the previous three. To that end, the series will debut in two parts. Volume One will arrive May 27 with seven episodes, and Volume 2 will follow with two more episodes on July 1.