, Netflix's eerie horror pastiche that mixes elements of Steven Spielberg, Stephen King and John Carpenter, has been the surprise hit of the summer - and it's coming back for a second season in 2017, it was announced earlier this month.
A new video, posted on the Stranger Things Twitter page, has also confirmed the episode titles for the new season, triggering furious speculation among fans of the show.
Created by the Duffer brothers, the series is set in small-town Indiana in 1983, and spins a nostalgic yarn of missing children, psychic phenomena, and things that go bump in the night.
If you're reading this, then the likelihood is that you've made it to the end of season one, with Eleven (Millie Bobby Brown) having just sacrificed herself to defeat the faceless creature, and Will (Noah Schnapp) recovering from his ordeal in the Upside Down.
Here, then, is what we know - and what we're hoping to find out - about the second series, which co-creator Matt Duffer has said will be "a little bit different... a little bit darker".
Two young new faces have been added to the cast of season two
Meet Sadie Sink and Dacre Montgomery, the newest two cast members of Stranger Things season two. Netflix has announced they will join the existing young actors for two brand new roles.
Sink will play Max, "a tough and confident girl whose appearance, behaviour and pursuits seem more typical of boys than of girls in this era. She has a complicated history and is generally suspicious of those around her".
Sink began her career on the stage, playing the title role of Annie and appearing opposite Helen Mirren in Stephen Daldry's production of The Audience. She went on to have roles in the NBC series American Odyssey, Netflix comedy The Unbreakable Kimmy Schmidt, and dramas Blue Bloods and The Americans.
She will next be seen in the upcoming feature films The Glass Castle and The Bleeder.
Montgomery, on the other hand, has been cast as Billy, "Max's hyper-confident, and edgy older step-brother. He steals girlfriends away from their boyfriends, is great at drinking games, and drives a black Camaro. But lurking under his apparent charisma, is a violent and unpredictable nature".
Originally from Australia, Montgomery has another big role ahead of him: he's set to play the red power ranger in the forthcoming movie reboot.
And that's not all. We'll also be seeing more of the characters Will (Noah Schnapp) and Steve (Joe Keery) as both have bumped up from "recurring character" to "series regular".
Is Millie Bobby Brown going to be in season two?
The end of season one left fans of Eleven - notably her admirer Mike - in flux: would she return for the next season, or had the telekinetic child left this dimension for another?
Millie Bobby Brown, the 12-year-old British actress who plays her, has cast her second season involvement into doubt after an interview with Lorraine on Thursday.
"I'm not sure if I'm going to be in it but it's fantastic, has great writers and directors... it will be good," she told the chat show host.
How many words did she say in season one?
She may be the beating heart of the show, but Eleven is hardly the loquacious type.
Indeed, according to Redditor ValdemarSt, Millie Bobby Brown's character only musters 246 words in the entire first season. But, hey, why speak when you can look this intense all the time?
Who are the new characters?
have managed to glean some information about the casting in the new series:
Max (aged 12-14) is described as "tough and confident" and instead of riding a bike like Dustin (Gaten Matarazzo), Mike (Finn Wolfhard), Will and Lucas (Caleb McLaughlin), Max will use a skateboard to get around Hawkins. Could she be the subject of the episode called Madmax?
Max's older brother Billy shares her traits. The "very muscular and hyper-confident" Billy drives a Camaro, but that's all we know about him so far.
There's also a third new addition to the Stranger Things cast: Roman, a gender-neutral role for an actor in their thirties who "suffered a great loss at an early age and has been seeking revenge ever since".
The question mark continues to hang over Eleven's involvement after the dramatic events of season one, with the Duffer Brothers saying her role remains "up in the air". What does Max's introduction mean for Eleven and the rest of the boys?
Meanwhile, we imagine Millie Bobby Brown will be keeping busy regardless - especially after her highly impressive cover of Nicki Minaj.
What does the casting call reveal about season two?
According to the call posted in Backstage, the production team are on the hunt for 1980s-looking people (duh!), especially "females willing to cut their bangs".
Does this mean we might more characters like Eleven, with buzz cuts and telekinetic powers? Read into it as you will.
What are the new episode titles?
Good news: this time round, we're getting an extra helping of Stranger Things. The second series will consist of nine episodes, in contrast to season one's eight.
• The boy who came back to life
• The Pumpkin Patch
• The Palace
• The Storm
• The Pollywog
• The Secret Cabin
• The Brain
• The Lost Brother
Who is 'The Lost Brother'?
Fans have already been poring over the episode titles for season two to try and work out some plot clues.
Most intriguing is the name given to the final episode: The Lost Brother. On Reddit, fans are suggesting that this could be a previously unmentioned biological brother of Eleven. Or could it be a reference to the other children who were presumably experimented on at the Hawkins National Laboratory?
Speculation is mounting, too, that Mike may find himself in the Upside Down in search of the missing Eleven: "Eleven is gone," wrote one user. "Perhaps Mike ends up where ever she is? And if it is indeed the upside down, then Will may offer glimpses into their whereabouts."
What is a Pollywog?
Not to be confused with the aquatic Pokémon character Poliwag, a Pollywog is actually less mysterious than it sounds: it's another name for a tadpole.
Remember that slug that Will coughed up in the stomach-churning climax of season one?
Perhaps the Pollywog is a "demogorgon" at laval stage and it's currently using Will's body as an incubator Alien-style...