Last summer it was “Mr. Robot” and “UnReal.” This summer, TV’s biggest surprise sensation has been Netflix’s ’80s set thriller “Stranger Things.” A unique mix of adventure, horror, teen angst, and adult drama, the series seemed to come out of nowhere and almost instantly developed a rabid fanbase when the season’s eight episodes hit the streaming service July 15. Part of the credit belongs with the largely fresh-faced cast, including Millie Bobby Brown as the enigmatic Eleven, a young girl who breaks free of her top secret science experiment prison, and a welcome comeback for ’90s icon Winona Ryder, playing radically against type as the distraught mother of a missing boy. Variety spoke with Ryder and Brown at the recent Television Critics Assn. press tour about the show’s breakout success, working with wunderkind twin brother creators Matt and Ross Duffer, and those haunting Christmas lights.

Winona, you’re not on social media. Have you followed the reaction “Stranger Things” has had this summer?

Winona Ryder: No, but people have shown me things.

Millie BobbyBrown: It’s been amazing. You got an A+ from Stephen King.

Ryder: That was crazy.

Brown: Not only social media, but reporters and press in general have been so supportive. The fans — apparently they’re called the Strangers.

Ryder: What is that?

Brown: I had no idea what they were called, and I said, “We need to find a name.” Because, like the Taylor Swift fans are called the Swifties …

Ryder: I didn’t know that. The Swifties? Like a Swifty Picker Upper? I have one of those to clean my house.

Brown: [laughs] She thought Snapchat was chips.

Ryder: Because in “Heathers” we had the Snappy Snack Shack. It was the 7-Eleven place. I thought it had something to do with food.

“It’s amazing because you see so many great reviews about the show and about [Winona]. And IMDb is crazy. Winona’s number five.” MILLIE BROWN

Have you seen Snapchat now?

Brown: We were doing Snapchat on lunch. I have the best picture of her, with the bee [filter]. I got you at the right time. She got so scared.

Ryder: It’s like the mirrors when you go to the fair and they have those weird reflections, you’re tiny or super stretched.

Brown: Obviously, Noni’s not on social media and I am. It’s amazing because you see so many great reviews about the show and about Noni and really everyone. And IMDb is crazy. Winona’s number five.

Ryder: I didn’t know about the numbers.

Brown: It’s basically like who’s most searched on IMDb.

Ryder: Oh, God.

Brown: When I started in the industry I was in the millions.

Ryder: It’s been overwhelming but in a really great way. I was actually sort of suspicious at first. I’d never experienced anything like it. It’s been a long time since I’ve been in something that was getting so much attention. And back then it was a different kind of attention. We’d stay up all night and wait for the three papers, and have someone read them first, like, “Is it OK?”

When you both signed on, you only had one episode to go off of?

Ryder: Yeah. But I’m suspect — they had to have written more, right? Can you get a show with just one script? I don’t know. A lot of friends of mine are on shows, or have been, and the one thing I remember when I first met with [creators, the Duffer twins] was thinking, “I don’t want to find out some big dark secret that would make me go, ‘I would’ve played it so differently!’” That’s happened to a lot of friends of mine. Like, “I’m the killer?” They’ll find out at a table read. I’ve known so many people who have had that experience. [The Duffers] didn’t tell me everything, but they told me enough. I said, “You have to let me know if there’s something that would affect the way I play her.” They were great in the way they helped me construct a backstory.

Brown: It’s definitely hard to trust someone with your character. They’re two brothers, they’re so young, but I had no idea they’re geniuses. They’re literally geniuses.

Ryder: They’ve never been tested to find out if they’re fraternal or identical. Isn’t that interesting?

I did read that. It’s weird.

Ryder: I’ve always been fascinated with twins. I would, like, want to know.

Brown: They’re definitely not identical. I can tell them apart very easily, especially by their personalities.

Ryder: It took me a little while… especially when Matt didn’t have the …

Brown: … the gray hair. I can tell Ross because Ross is more serious, and Matt’s more silly.

Ryder: They have that weird twin language, where you’re talking to one and the other will answer. They have this telepathy type thing. I saw it with Tim Burton. He’d do this thing where he would go [gestures], “You know?” And somehow I would know. This was before monitors, so he’d be next to the camera and he’d kind of do [the scene] with you almost.

Was that from the beginning with Tim? Or did it grow over time?

Ryder: It was there. I think he’s like that with certain actors. He can be incredibly articulate too. The Duffers can be super articulate or very straight to the point. I was really impressed with how they were with each other.

Brown: And really courteous to their cast as well. That was really special, We each had a bond with them. They were like my big brothers, they’d get on my nerves, but I loved them. And especially with the boys I think they really bonded in general. When I act I like to visualize what the director’s thinking. They lived in North Carolina and they experienced [small-town suburbia]. They can tell me stories and I’ll visualize it completely.

Ryder: There are certain directors who will start talking to you about something and suddenly you’ll be ready to roll and you’ll realize it was very specific. Scorsese would talk to me about this movie “The Heiress” with Olivia de Havilland. We were talking about this scene in it, and suddenly we were rolling. It was very intentional, and I didn’t realize — because we talk old movies all the time.

He was getting you to a place.

Ryder: Yeah. And [the Duffers] are great about that. They know their movies.

Winona, you have what’s become an iconic moment in episode three when Joyce is communicating with Will through the Christmas lights.

Ryder: I don’t think I realized, I remember something was going on, but you’re in that weird state of emotion. The way the set was built, the camera couldn’t really get in there with me. It was dark and I was looking down, I couldn’t cheat the look. People keep pointing that scene out.

“It’s been a long time since I’ve been in something that was getting so much attention. And back then it was a different kind of attention.”

Winona Ryder

You didn’t realize it would be a big scene?

Ryder: Or that people would respond to it so much. At the time I remember, having to soar from joy to realizing [Will] is in trouble, and the helplessness. It was very emotional. Bob [Gorelick] and Jamie [Pair] and Clyde [Bryan] are our camera guys, they’re the people you’re physically closest to, and they’re just great guys. They were so great and really helpful in giving me those moments to get to where I needed to go. They were real-old school pros, and very protective.

How intense was the role compared to other parts you’ve played? And having to sustain it over eight episodes?

Ryder: It’s certainly the first time I’d played a mother who is going through something like that. I’ve done emotional stuff before, but it was much different. It was challenging and a lot of work. I’m always super aware of little details — and they were really on it with the details, we had a great production designer. When I’m supposed to call [ex-husband] Lonnie, I was like, “Wait, if I don’t really know where he is, I’d need a piece of paper with the number.” They got me a piece of paper. But the dialing — they only used like three numbers because it takes forever with the rotary phone. [Laughs.] I was like, “You guys, it’s long distance. It has to be ten numbers.” To me that was a big thing in that time. It was a character-builder. Now you can construct a perfect text …

Brown: I had no idea what that phone was.

Ryder: Back then you’d be like, “OK, what am I going to say?” I remember the first time I called a boy, it was like [deep breath] “OK.” You got that time it took to dial to figure out what to say. But you know, I think they only used the three numbers.

Everyone wants to know what’s next for these characters. Have you heard any plans for future seasons?

Ryder: I’m dying to know.

Brown: Same. We’re exactly like you guys, we have no idea. But hopefully…

Ryder: When are they gonna say that? It has to be soon.