A mysterious Dome—invisible, electrified, and impenetrable—descends over the town of Chester’s Mill, or, as it is known to the locals, The Mill. Even more bizarrely, the Dome contours exactly to the borders of this small town in Maine. In Stephen King’s expansive novel Under the Dome, he investigates what happens when a town is cut off from the larger world, held captive not only by the mysterious Dome but also by the designs of a few power-hungry citizens. The protagonist, Dale Barbara, known as Barbie, has been working in The Mill as a short-order cook for a brief time, but he has decided to leave after a confrontation with the son of the most powerful man in town, Big Jim Rennie. Barbie’s plans are stopped short by the appearance of the Dome, and once the townspeople realize that they are trapped, civic order and democratic principles disintegrate quickly. Rennie takes the opportunity to amass power and to pin his many crimes—including murder—on the outsider, Barbie. However, with the help of local newspaper editor Julia Shumway, some courageous teens, and a few other like-minded citizens, Barbie escapes from prison, and the group discovers the source of the Dome—an alien generator. Published in 2009, Under the Dome contains many of King’s hallmarks: violence and gore; crazed villains and flawed heroes; horror and redemption. It was made into a television series of the same name that aired for three seasons, from 2013 to 2015.

This guide refers to the 2010 Gallery Books paperback edition.

Content Warning: The source material depicts sexual assault, graphic violence, substance abuse, and suicidal ideation. It also features offensive language directed at women and LGBTQ+ people.

Plot Summary

When the Dome descends on Chester’s Mill, chaos immediately ensues: a small aircraft is destroyed; a woodchuck is cut in half; a local woman loses a hand. It takes little time for the people of The Mill to figure out that they are trapped, fully cut off from the outside world. Even the air that they breathe slowly becomes stagnant, as fresh air can penetrate just barely.

Dale Barbara is looking to leave Chester’s Mill after a confrontation with Junior Rennie and his friends, but Second Selectman Big Jim Rennie is seeking to consolidate his firm grip on power over what he sees as his town. The two men are already at odds over the confrontation—Junior is Rennie’s son, of course—and Rennie takes every opportunity to besmirch Barbie’s reputation. Rennie is deeply corrupt, having misappropriated town funds and paid off officials to make irregularities disappear. He has also built a thriving methamphetamine lab on the grounds of evangelical radio station WCIK, where the Chef (Phil Bushey) cooks up product to be sold all over the Eastern seaboard. Rennie works with the collusion of First Selectman, Andy Sanders, and Reverend Coggins of the evangelical church. When Coggins confronts Rennie about their illegal activities, taking the Dome as a sign from God to confess, Rennie bludgeons him to death with a gold-plated baseball souvenir.

Meanwhile, his son, Junior, has also committed murder—an act linked to the incident with Barbie—when the Dome first descends. He witnesses his father’s brutal performance and says he will help in the disposal of the body: He has already stashed his two victims in the pantry of his first victim’s house, so it should be no problem. Rennie decides that he will pin the crimes on Barbie, which should be easy because Barbie is already an outsider. The townspeople are fearful, even desperate, and Barbie is not one of them. Junior conveniently finds Barbie’s old dog tags—he is an Iraq War veteran—and plants them in the hand of one of the victims.

Yet Barbie is not without his share of support. He is called back to duty by the president of the United States, his rank is elevated, and he is tasked with taking over the martial law established. The local newspaper editor, Julia Shumway, and some other townsfolk also support Barbie and are intent on resisting Rennie’s power. Rusty Everett, the physician’s assistant at the local hospital, his wife, Linda, and her police-officer colleague, Jackie Wettington, along with Reverend Piper Libby of the local Congregational church and a group of clever teens, understand that Barbie, not Rennie, is working for the greater good. Rennie has amassed what amounts to an army of untrained cops, including his homicidal son Junior and some of his hypermasculine buddies, to institute a reign of terror and autocratic control rather than to preserve the civic order. He finally has Barbie arrested, though Barbie’s associates help to free him—but only just in time. As Junior comes to kill him in his cell, Barbie’s friends arrive, and Jackie shoots Junior before he can fire his weapon.

Meanwhile, the Chef has been joined by Andy Sanders in his meth-induced paranoia and visions of apocalypse. Sanders has lost both his wife and his daughter in the chaos of the Dome isolation, and he has nothing left to lose. While Rennie has decided to shut down the drug operation—the town needs the propane tanks that fuel the endeavor, now that they are cut off—Chef has no intention of relinquishing his tanks or his drugs. He and Sanders are preparing for a confrontation.

Eventually, the brave teen explorers and their adult allies discover that the Dome is generated by alien forces, which explains the many prophecies, premonitions, and visions experienced by the people of The Mill and the failure of the military to take down the Dome with missile strikes and high-powered acid. A Visitors Day is organized for family members of the trapped townspeople to gather at the Dome, with the hope that the publicity will shame Rennie into relinquishing his control. The stress of the Dome weighs heavily on the residents; there are many more deaths in town, some by suicide.

Barbie and his cohort investigate the alien box that generates the Dome. It reveals eerie alien faces who seem to be laughing at the humans, and Barbie determines that they are all trapped in a cruel experiment. While the aliens show no signs of relenting or releasing their subjects, the town’s ultimate demise will come about due to explicitly human action: on Visitors Day, Rennie’s men invade the WCIK radio station, intending to take down the Chef, but he and Sanders push the button that detonates the Chef’s makeshift bomb. The explosion, within the enclosed area of the Dome, destroys almost all the remaining residents of Chester’s Mill. Only when Julia and Barbie beg the aliens for mercy do they release the Dome, allowing fresh air to flow in to greet the two dozen or so survivors of the town’s 2,000 original residents.

The events in the lengthy novel occur between the dates of October 21 and October 28, in an unnamed year (though a character is spotted reading about new 2012 car models at one point) in a named but purposefully generic or “everyday” town. These elements of setting help establish the intended universality of the novel’s themes of Corruption and Control and The Dissolution of Democracy.