Under The Dome, the series that ushered in a new business model for original summer scripted series on CBS and helped blur the lines between in and off-season with big premiere ratings, is ending its run. The upcoming Season 3 finale on September 10 will serve as a series finale as CBS has opted not to order a fourth season. The cancellation of Under The Dome bodes well for CBS’ other bubble summer drama, Extant, whose renewal chances have now significantly improved. (CBS brass also have been bullish on the sci-fi series’ creative reboot in Season 2.) Freshman Zoo, the strongest of the three this summer, has been expected to be renewed all along. CBS already has ordered a new drama series for next summer, BrainDead. Word is that, if the network only brings back two existing dramas, there may be room for a second new drama series next summer.

CBS LogoUnder The Dome was a phenomenon when it launched in June 2013 with 17.8 million Live+7 viewers tuning in for the premiere, the highest summer drama debut in 21 years and the second-highest-rated opener of the 2012–13 season. The adaptation of the Stephen King novel could not sustain the initial ratings highs and has been on decline ever since. (It also has drawn gripes from fans with some of its plot twists.) Still, Dome remained one of the most watched summer shows for the past three summers. It also introduced a new model, with the TV premiere of an episode followed by a streaming debut just a few days later, which, paired with strong international sales, made Under The Dome profitable for producer CBS TV Studios even without its CBS run. CBS and CBS Studios replicated the model with two other series, Extant and Zoo. Amazon was the studio’s streaming partner on Dome and Extant; Netflix is carrying Zoo. All three seasons of Under The Dome will continue to be available for unlimited streaming on Amazon’s Prime Video where Dome has been a solid performer.

“Two years ago, Under The Dome broke new ground in the summer and became an instant hit on CBS, as well as with viewers around the world,” said Nina Tassler, Chairman, CBS Entertainment. “Dome’s event storytelling and multi-platform business model paved the way for more original summer programming with the successful rollouts of Extant and Zoo. We’re excited to present the final chapter in Chester’s Mill as the story comes full circle, with the Dome coming down as dramatically as it went up.”

Per CBS, “in the series finale, when the Dome comes down, many questions about its origin and power will be answered, as two groups of residents engage in one final conflict that some won’t survive.” Here is a promo for the finale:

Under The Dome stars Mike Vogel, Rachelle Lefevre, Dean Norris, Eddie Cahill, Alexander Koch, Colin Ford, Mackenzie Lintz and Kylie Bunbury star. The series is produced by CBS Television Studios and Amblin Television. Steven Spielberg, Neal Baer, Justin Falvey, Darryl Frank, Stacey Snider, Tim Schlattmann and Peter Leto are executive producers.