Netflix is returning to the Upside Down.

The streaming giant has renewed the Duffer brothers' breakout hit Stranger Things for a third season. A return date has not yet been determined for the supernatural drama about the happenings brimming beneath the surface of a small American town.

While Netflix — like fellow streamers Amazon and Hulu — does not release viewership information, measurement leader Nielsen cited an audience of 15.8 million viewers who watched the season two premiere of Stranger Things within three days of its launch. (And nearly 11 million of them were among the key adults 18-49 demographic.) Nielsen also found that 361,000 Netflix subscribers streamed the entire nine-episode second season within 24 hours of its debut. (Netflix declined comment on the Nielsen findings.) Stranger Things 2 also was crowned the most popular show in the country, according to data company Parrot Analytics.

Still, even without ratings from Netflix, Stranger Things ranks as the service's biggest franchise. The show, which collected 18 Emmy nominations (and took home five awards), is pulling Netflix into a new business with a series of licensing deals for clothing, posters, toys and collectibles. Given the breakout success of the program (which is owned in-house) and lucrative licensing deals, Stranger Things' child stars are said to be banding together to renegotiate their contracts for upcoming seasons.

In September, sources told The Hollywood Reporter that Finn Wolfhard, Millie Bobby Brown, Gaten Matarazzo and Caleb McLaughlin each got $30,000 per episode for the first and second seasons with a bonus — less than six figures — once it became clear that the show was a phenomenon. While the cast is signed for six years, talent reps say a renegotiation will happen in early 2018. One question yet to be addressed is whether the show's breakout, 13-year-old Brown, will negotiate separately from the other young stars.

Netflix had hoped to film seasons three and four back-to-back in a move to work around any potentially awkward adolescent transitions for its young cast. Creators Matt and Ross Duffer and executive producers Shawn Levy and Dan Cohen quickly nixed that idea.

After launching with immediate impact in July 2016, Stranger Things released its nine-episode second season in October, days before Halloween. The events of the season lined up with the holiday theme, too, as the second episode, "Trick or Treat, Freak," focused on the four young kids at the heart of the series celebrating Halloween in full Ghostbusters regalia.

In the context of the show, Stranger Things 2 took place slightly less than a year after the events of the first season. Will that same formula follow suit for season three? The final image of the most recent episode — the Mind Flayer lording over Hawkins Middle School from the shadow dimension known as the Upside Down — could lead viewers to believe the next season will pick up immediately after the Snow Ball dance. But in a conversation with THR, the Duffers confirmed some form of time jump will occur between seasons.

"Even if we wanted to hop into the action faster, we couldn't," Matt Duffer previously told THR. "Our kids are aging. We can only write and produce the show so fast. They're going to be almost a year older by the time we start shooting season three. It provides certain challenges. You can't start right after season two ended. It forces you to do a time jump. But what I like is that it makes you evolve the show. It forces the show to evolve and change, because the kids are changing. Even if we wanted it to be static and we wanted to continually recycle the same storyline — and we don't — we would be unable to, just because the kids are changing. It's cool, though. The audience is going to be able to watch these kids come of age every year. The closest example is Harry Potter. Watching those kids and actors grow up in front of the camera was, to me, very powerful. I mean, I wasn't a kid when I experienced that, and I can only imagine if you were a kid and you were their age, it would have been even more powerful. That's what I'm excited about. It's a long way of saying that yeah, we're going to do a time jump."

Set in a small town called Hawkins, Indiana, in the 1980s, Stranger Things focuses on a crew of kids who call themselves "The Party," including leader Mike Wheeler (Wolfhard), the frequently endangered Will Byers (Noah Schnapp), straight-shooting Lucas Sinclair (McLaughlin) and eternally upbeat Dustin Henderson (Matarazzo). In the first season, Will goes missing, abducted into the shadowy Upside Down. He's saved thanks to the arrival of Eleven (Brown), a young girl with telekinetic powers. Season two sees Eleven enhancing her abilities while the threats of the Upside Down resurface and expand. Unlike the first season, season two ends in such a way that there's very little clear direction about the future of the series — exactly the way the Stranger Things creators envisioned it.

"Last year, we had a lot of little cliffhangers at the end of the season. We didn't want to do that again," Matt Duffer told THR. "We didn't want to box ourselves in for season three. We wanted to be able to start season three on a very clean slate."

Follow THR.com/StrangerThings for full coverage of season two and beyond.