under the dome season 3 spoilers
Julia (Rachelle Lefevre) and Big Jim (Dean Norris) will go head-to-head with The Kinship in the series finale of "Under the Dome." CBS

The dome is finally coming down. After three seasons of being trapped under a mystical force field, the surviving residents of Chester’s Mill will finally taste freedom in the series finale of the hit CBS summer smash, “Under the Dome.” But, according to the synopsis for episode 13, titled “The Enemy Within,” their independence will come at a cost… and a deadly one at that.

“As the dome in Chester's Mill comes down, The Resistance, led by Barbie (Mike Vogel), Julia (Rachelle Lefevre) and Big Jim (Dean Norris), makes a final attempt to protect the outside world from the infected townspeople in The Kinship, including Sam (Eddie Cahill), Junior (Alexander Koch), and their new queen,” the summary reveals, adding that some of the beloved townies “won’t survive” the fatal altercation between the two groups.

But that’s not all we know about the final installment of “Under the Dome.” In addition to learning that our burning questions regarding the dome’s origin and power will be answered (seriously, it’s about time) viewers can also catch a glimpse at the drama that’s set to go down in “The Enemy Within” with the recently released series finale promo photos. Check out the images below:

CBS confirmed in August that the supernatural drama, based on Stephen King’s same-named, best-selling novel, would be coming to an end.

“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,” Nina Tassler, chair of CBS Entertainment, said in a statement. “'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.”

Although the cancellation came as surprising news to some, it didn't shock those who saw that the viewership for “Under the Dome” had dramatically dropped since the show’s highly-watched premiere episode. The series kicked off in 2013 with 13. 5 million viewers tuning in, according to TVLine. But numbers dropped to an average of 4.6 million when the CBS thriller made its Season 3 debut.

“Under the Dome” will airs its series finale on Thursday, Sept. 10, at 10 p.m. EDT on CBS.