Patrick, a fashion photographer, receives an intriguing letter from his sister, Caroline, who is recovering from addiction. She invites him to visit Eden Parish, a utopian community free from drugs, established by a charismatic religious leader known simply as Father. Driven by curiosity, Patrick decides to investigate the compound, which is only reachable by helicopter, as noted by his coworker Sam, who describes it as being in "a remote part of the world." Collaborating with cameraman Jake and Sam, they contemplate making a documentary about this mysterious place.
Their journey begins smoothly, but the helicopter pilot warns them about the need to return promptly the next day. Upon arriving at the airfield, they find that the guides are caught off guard by the presence of a film crew, as they had only prepared for Patrick's arrival. The guides promptly contact Father, who allows their entrance into the commune.
Once at the commune, they encounter delays from armed guards, which makes Jake and Sam uneasy. However, their concerns are alleviated when Caroline arrives and warmly welcomes them, apologizing for the earlier confusion. Caroline joyfully reunites with Patrick, while Jake and Sam are assigned a cabin of their own to settle in.
After getting comfortable, Jake and Sam embark on their mission to interview the community members. Several residents share their uplifting stories, crediting Father for saving them and providing a renewed sense of hope. They learn from Wendy, the commune's nurse, that the medical center is well-stocked, funded by donations from the residents, many of whom have sold their possessions.
Despite their initial skepticism, the filmmakers can't help but notice the apparent happiness of the commune's members and their accomplishments. Caroline arranges an interview with Father, and Sam prepares a set of questions. To their surprise, Father insists that the interview take place during a public gathering. Initially, he greets the crew with warmth, answering their questions directly. However, as the conversation progresses, his demeanor shifts, becoming evasive and mildly threatening. As the interview nears its end, Father brings up Sam's pregnant wife, causing Sam to fumble and lose control of the situation. With a polite yet firm demeanor, Father ends the interview amid roaring applause from his devoted followers.
During a festive party later, a young mute girl named Savannah passes a note to Sam, signaling for help. Meanwhile, when Jake and Sam search for Patrick, they find him distracted, engaging in a casual sexual encounter, while an intoxicated Caroline reveals that they need Patrick's financial support. As the filmmakers delve deeper into the commune, they stumble upon a group of dissenters who reveal troubling allegations of abuse and brainwashing. Jake is hesitant to intervene, but Sam insists they assist despite the lack of space on the helicopter. Distrust for Father and the commune grows as they spend a restless night filled with anxiety.
The following morning turns chaotic when the dissenters grow rebellious. Sarah, Savannah's mother, urges that they rescue her daughter. Jake makes his way back to the helicopter to stall its departure, but the pilot refuses to help. Just then, gunshots erupt, prompting Jake to flee into the forest and circle back to the helicopter, where the injured pilot urges him to get the others.
Back at the commune, Sam tries to break up a fight only to be attacked by a guard. An enraged Caroline denounces Sam, leading him to be taken hostage. In a chilling turn of events, Father gathers the community, forcing everyone to drink cyanide-laced beverages. Those who refuse face execution by shooting. In a tragic moment, Patrick, held nearby, falls victim to Caroline, who injects him with a syringe.
Upon returning to the camp, Jake discovers that very few remain alive, with armed guards watching over the chaos. In a harrowing sequence, he finds Sarah and Savannah hiding in a cabin; to prevent her daughter from being killed, Sarah takes Savannah’s life, only to be shot herself while Jake hides. Jake encounters Caroline, who expresses her hopelessness before self-immolating in a despairing act.
Finally, tensions escalate as Jake confronts Father and finds Sam bound to a chair. Assigning blame to Jake and Sam for the disaster, Father points a gun at himself, leading to a shocking suicide. As they attempt to escape, they are nearly shot by a remaining guard but are saved when another guard intervenes, killing the would-be shooter. The remaining guard tells Jake and Sam to flee as he stays behind to set the commune ablaze.
As they soar away in the helicopter, the filmmakers witness the flames consume Eden Parish. The screen fades to black, revealing the grim toll of the tragedy: 167 people perished during the massacre, leaving Sam Turner and Jake Williams as the only survivors, with their documentary serving as the sole firsthand account of the catastrophic events that unfolded at Eden Parish.
