这部心理惊悚题材的影片故事设置在1950年代加州沙漠里的一个与世隔绝的乌托邦式群体当中，讲述一位家庭主妇(Pugh饰)意外地发现了看似平静的生活中的恐怖秘密。
Alice and Jack Chambers are a young, happy couple in the 1950s, living in an idyllic neighborhood of the company town of Victory, California, which has been created and paid for by the mysterious company of the same name for which Jack works. Every day, the men go to work at Victory Headquarters out in the surrounding desert, while their wives (Alice, her friend Bunny, the pregnant Peg, newcomer Violet, and Margaret) stay home to clean, relax, and prepare dinner for their husbands. The women are discouraged from asking questions about their husbands' work, and are told not to venture out to Headquarters due to the "dangerous materials" the company works with: Margaret has become an outcast among the other wives after taking her son out into the desert, resulting in her son's apparent death. Margaret claims that Victory took her son from her as punishment, but these claims are dismissed by the others as a trauma-induced paranoia. While attending a party hosted by Frank, Victory's enigmatic founder and leader, Alice sees Margaret's husband attempting to give her medication. Later, while Alice and Jack secretly have sex in Frank's bedroom, Alice realizes Frank is observing them but says nothing.
One morning, while riding the trolley across town, Alice witness a red Biplane crash somewhere out in the desert. Alice disembarks and rushes into the desert to help, accidentally stumbling on Victory Headquarters - a small building covered in mirror-like windows. After touching one of the windows, she experiences surreal hallucinations before waking up back home later that night to find Jack preparing their dinner. In the following days, Alice begins to experience increasingly strange occurrences: she is almost crushed between a window and a moving wall, and she finds a box of eggs to be filled only with hollow shells. She receives a phone call from Margaret, who claims to have seen the same thing Alice had. Later, during a dance lesson lectured by Frank's wife Shelley, Alice sees a vision of Margaret violently banging her head against a mirror: she rushes back to their neighborhood just in time to see Margaret slit her own throat and fall from the roof of her house. Alice is dragged away by strange men in red jumpsuits before she can reach Margaret's body.
Alice attempts to explain the events to Jack, but Jack dismisses it, explaining that Margaret simply fell while cleaning the windows and is perfectly fine and recovering in hospital with her husband, who has been forced to leave the Victory project in order to take care for her. This version is further corroborated by the town physician Dr. Collins, who claims to have treated Margaret and attempts to give Alice the same prescription drugs. Alice later breaks into Dr. Collins' briefcase and finds a heavily-redacted medical file for Margaret, which she then burns in frustration. Alice becomes increasingly paranoid and confused, feeling as if Frank is watching her every move. During a special Victory event in which Frank gives Jack a special promotion, Alice has a breakdown in the bathroom and is comforted by Bunny. Alice attempts to explain everything to Bunny, but Bunny reacts angrily, accusing Alice of being selfish and attempting to ruin everything for everyone, pointing out she sounds "just like Margaret."
Some time later, Alice and Jack invite the rest of the neighborhood (except Bunny and her husband Bill) to dinner, with Frank and Shelley as special guests. Frank speaks privately with Alice in the kitchen, intimating that she's right in her suspicions, and confessing that he's been waiting for someone like her to challenge him. Spurred on by Frank's confession, Alice attempts to expose him and the inconsistencies in Victory over dinner. Instead, Frank gaslights her, making her look delusional to the other guests. In the aftermath, Alice begs Jack to take them both away from Victory. Jack initially agrees, but when Alice gets in the car, he lets her be taken away by Frank's men. Dr. Collins forces Alice to undergo electroshock therapy. During the procedure, Alice sees visions of herself in another life - as a present day surgeon named Alice Warren, who lives with the unemployed Jack and struggles to make ends meet.
Alice returns to Victory, apparently cured of her "hysteria", and reunites with Jack and with Bunny. However, as Alice resumes her normal life, she continues to have hallucinations and flashbacks. Alice later remembers the whole truth: that Victory is a simulated world created by Frank, and that Jack has kidnapped her and forced her into the simulation in the hope they can lead a perfect life together. When Jack realizes she knows the truth, he claims he did this for her as she was miserable in her real life, but Alice is enraged that Jack took away her autonomy. Jack hugs Alice, begging her to forgive him, but begins to crush her, and Alice kills him with a glass tumbler in self-defense, killing Jack in the real world as well.
Frank is alerted to Jack's death and sends his men to capture her. Alice is found with Jack's body by Bunny, who explains that she has known all along that Victory is a simulation but chooses to stay so she can be with her children, who are dead in real life. Bunny tells Alice to flee to Victory Headquarters, which is an exit portal from the simulation, and holds off Bill when he attempts to attack Alice for killing Jack. The other wives gradually begin to realize the truth as their husbands start to panic. Alice steals Jack's car and drives out towards Victory Headquarters, chased by Dr. Collins and Frank's men. She tricks Dr. Collins into killing himself and several others in a car crash. At their house, Shelley stabs Frank to death, claiming it is now "her turn". Alice makes it to Victory Headquarters, where she encounters a vision of Jack asking her to stay. Alice ignores the vision and rushes to the window just before Frank's men reach her. Over a black screen, the sound of Alice gasping for air is heard, implying she escaped.
