The Duffer brothers have signed a multiyear overall pact on the back of their 1980s-set sci-fi homage, which is reportedly one of the streamer's most-watched original series.

Netflix's time in the Upside Down will continue.

The streaming giant has handed out a fourth-season renewal to the breakout hit Stranger Things and signed its creators, brothers Matt and Ross Duffer, to a multiyear film and TV overall deal that sources say is worth nine figures. The news arrives nearly three months after the third season of the 1980s-set sci-fi drama returned after more than a year off the proverbial air. A return date for season four has not been determined.

“The Duffer Brothers have captivated viewers around the world with Stranger Things and we’re thrilled to expand our relationship with them to bring their vivid imaginations to other film and series projects our members will love,” Netflix chief content officer Ted Sarandos said Monday in a statement. “We can’t wait to see what the Duffer Brothers have in store when they step outside the world of the Upside Down.”

Stranger Things is considered Netflix's most popular scripted original series. The streamer, which typically does not release viewership data, announced July 8 that some 40.7 million household accounts had watched part of season three since its July 4 launch — "more than any other film or series" in its first four days. It also noted that 18.2 million households had already finished all of season three. Measurement company Nielsen in December 2017 said that more than 15 million people watched the season two premiere within three days of its launch, with 11 million of those viewers in the key adults 18-49 demographic. Stranger Things season two was also crowned the most popular show in the country, per data company Parrot Analytics.

"We are absolutely thrilled to continue our relationship with Netflix. Back in early 2015, Ted Sarandos, Cindy Holland, Brian Wright and Matt Thunell took a huge chance on us and our show — and forever changed our lives," the Duffers said in a joint statement. "From that first pitch meeting to the release of Stranger Things 3, the entire Netflix team has been nothing short of sensational, providing us with the kind of support, guidance and creative freedom we always dreamed about. We can’t wait to tell many more stories together — beginning, of course, with a return trip to Hawkins!"

Still, even without formal analytics from Netflix, Stranger Things is easily the streaming giant's biggest franchise. The series remains an awards contender — it has collected 18 Emmy nominations (winning five) and created what is likely a multimillion-dollar licensing business of merchandising with a line of comic books and other consumer products.

Additionally, the castmembers of the drama have all seen their profiles rise thanks in part to the success of the show. The adult and young actors on the series all successfully renegotiated their contracts ahead of season three (a common practice for a hit show) to earn massive pay raises. The young castmembers — Finn Wolfhard, Gaten Matarazzo, Caleb McLaughlin and Noah Schnapp — secured roughly 12 times their previous deals and earn $250,000 per episode. Adult stars Winona Ryder and David Harbour saw their salaries climb to $350,000 per episode. Breakout Millie Bobby Brown is said to earn somewhere between both levels. Additionally, executive producer Shawn Levy has also cashed in on the show's success, and in late 2017 signed a four-year, seven-figure overall deal with Netflix.

In the larger scheme of things, it's unclear if season four will be the last for Stranger Things as the Duffers have been open about the drama not being a long-running show. The duo have said over the years that they see it running anywhere between four and six seasons.

The Duffers are repped by Morris Yorn.

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