“Under the Dome” will wrap up with its current season, as the season-three ender will serve as the series finale, Variety has learned. The drama, based on Stephen King’s novel, has been cancelled and will not return for a fourth season.

“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, chair of CBS Entertainment. “‘Dome’s’ event storytelling and multiplatform 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.”

The season-three finale on Sept. 10 will answer many questions about the dome’s origin and power, as two groups of residents will engage in one final conflict that some won’t survive.

First premiering in June 2013, “Under the Dome” opened to some of the best numbers for any summer series in years, but has consistently declined over the past two years. In live plus same-day, it averaged a 2.7 rating in adults 18-49 and 11.2 million viewers overall in its first season, but fell to a 1.6 in the demo and 7.2 million in season two and is currently averaging a 1.0 in 18-49 and 4.9 million total viewers.

This summer, “Dome” remains among the higher-rated scripted shows, and spikes on average by 80% in 18-49 (to 1.8) and about 60% in total viewers (to nearly 8 million) when going from same-night to “live plus-7,” according to Nielsen.

At the time of its first season premiere, CBS inked an SVOD licensing deal with Amazon Prime Video, and after the finale, all three seasons of “Under the Dome” will continue to stream on the service.

Last month at the Television Critics’ Assn. summer press tour, Tassler responded to reporters’ questioning the future of the series and though she teased the dome coming down, she kept the door open for discussion.

“Well, what I’ll tell you is the dome is coming down at the end of this season, but that opens up a host of other storytelling opportunities,” she said. “You just don’t know what will happen when the dome comes down. So we are not making a decision just yet.”

Mike Vogel, Rachelle Lefevre, Dean Norris, Eddie Cahill, Alexander Koch, Colin Ford, Mackenzie Lintz and Kylie Bunbury star in “Under the Dome,” which is produced by CBS Television Studios and Amblin Television with exec producers Steven Spielberg, Neal Baer, Justin Falvey, Darryl Frank, Stacey Snider, Tim Schlattmann and Peter Leto.

Watch the Season 3 finale promo right here:

Rick Kissell contributed to this report.