In America during an unspecified time period, Alice and Jack Chambers live in an idyllic 1950s-styled neighborhood of the company town of Victory, California. Every day, the men go to work at Victory Headquarters out in the surrounding desert while their wives (among them Bunny 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 told not to venture out to Headquarters. Margaret has become an outcast after taking her son out into the desert, resulting in her son's apparent death, although she claims that Victory took him from her as punishment. While attending a party hosted by Frank, Victory's enigmatic founder and leader, Alice sees Margaret's husband attempt to give her medication after an outburst at the party. Later, she sees Frank looking in on her and Jack while she is fingered in Frank's bedroom.

One morning while riding the trolley across town, Alice witnesses a plane crash out in the desert. She rushes to help and stumbles onto Headquarters, a small building covered in mirror-like windows. After touching one, she experiences surreal hallucinations before waking up back home later that night. In the following days, she experiences increasingly strange occurrences. She receives a phone call from Margaret, who claims to have seen the same thing Alice did. After rebuffing her, Alice sees Margaret slit her own throat and fall from the roof of her house. Before she can reach Margaret's body, Alice is dragged away by men in red jumpsuits.

Jack dismisses Alice's claims and says Margaret simply fell while cleaning the windows and is recovering. This story is further corroborated by the town physician, Dr. Collins, who attempts to give Alice prescription drugs. Alice becomes increasingly paranoid and confused, and during a special Victory event where Frank gives Jack a special promotion, she breaks down in the bathroom and is comforted by Bunny. Alice attempts to explain everything to her, but Bunny reacts angrily, accusing Alice of being selfish.

Some time later, Alice and Jack invite the rest of the neighborhood (except Bunny and her husband Dean) to dinner, with Frank and his wife Shelley as special guests. Frank speaks privately with Alice in the kitchen, insinuating that she is right in her suspicions. Spurred by his confession, she attempts to expose him 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 the men in red jumpsuits. Dr. Collins forces Alice to undergo electroshock therapy. During the procedure, she 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 and reunites with Jack, but continues to have hallucinations and flash-backs. She later remembers the whole truth: that Victory is a simulated world created by Frank, and that Jack has forced her into the simulation in the hope that 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, then attempts to strangle her, forcing Alice to kill him with a glass tumbler.