A man, Bobby, runs through the snowy woods at night as people with flashlights and dogs chase after him.
Five Months Earlier Bobby returns to his apartment and finds that Tracy is late, and ran a pregnancy test. It's negative, and she insists they should go somewhere where there's some space so they can raise a baby. Later they meet with friends Scott and Meryl for dinner, who mention they found a gated community, the Commons, that seemed perfect but wasn't right for them.
Bobby and Tracy go to check the place out in the suburbs and arrive at the locked gates. The gates open by themselves and they go in. The community person, Candace, gives them a tour and speaks of the Commons' virtues. She shows them a house, noting the previous owners transferred due to business. The house is furnished and Tracy is enthusiastic, but Bobby is skeptical. Candace says it's the only house available and suggests they fill out an application.
Two days later, Bobby returns home to find Tracy celebrating as they got the house. They sign an extensive personal conduct agreement and Bobby wonders what the catch is. Candace insists it's about security and family and they want people like Bobby and Tracy to invest in their community, which is based on hundreds of years of research and data. She notes there's a 97% chance the couple meet the Commons' needs based on 73 different criteria.
The couple sign and move in four weeks later as everyone enthusiastically greets them. That night, the couple enjoy the peace and quiet of the suburbs and make love trying to have a baby. The next morning their neighbors Phil and Debra Fabre visit, and Phil talks ominously they're having been there for the worst 12 years of his life. They've brought beer despite the early hour.
Later, Tracy goes to get coffee and talks to Arlene, who explains that they can pay whenever they want. As Arlene leaves with daughter, she's unaware that Candace is watching her on closed-camera monitors.
At Christmas, Bobby and Tracy host a party. Phil and his wife are there, and Phil is drinking heavily and raving. Debra slaps him and he collapses, shattering an end table. Bobby comes over and sees that Phil has no legs, and gets around on artificial limbs. The other neighbor men get Phil out of the house.
Several days later Bobby is jogging when he sees Debra, who says that Phil had to leave to tend to his ailing brother. That night, Bobby is flipping through channels when he gets a broadcast of his neighbors from across the street. The woman Sandra is undressing when a man approaches her, and her husband Ron barges in demanding to know what's going on.
Two weeks later, Bobby overhears a call from Arlene saying she'll set up Tracy with her OB because she's having problems conceiving. Bobby is upset but Tracy doesn't understand the problem that he has. There's a resident's group meeting that night and Candace is mediating between Ron and Sandra. Ron insists that he trusts her but the community says they can't trust Sandra. Candace says that the offended partner chooses the punishment, and Bobby objects that it's none of their business.
The next day, as Bobby is walking home he sees Sandra tied to a pole and wearing a pig's mask, while the neighbors throw garbage at her. The police officer say that the neighbors will help her and when Bobby confronts Ron, Ron says that Sandra choose the punishment. Bobby tries to help her but Sandra and the others say not to interfere. Later he runs into Sandra and Ron, who thank him for his help and wish him and Tracy well in having a baby.
Bobby returns home to find Candace waiting for him and Tracy. Candace wants to help with their pregnancy and says the residence agreement lets them intervene. Bobby reads the agreement and sees that it says residents have to conceive within six months of moving in. Two days later, Bobby and Tracy approach Candace and ask what happens if they don't conceive. She explains that they'd lose the house and have their credit rating destroyed. They call Scott who informs them there's no way out of the agreement, and Bobby says that Tracy doesn't know he's calling. Bobby asks Scott to help him find the previous owners.
Tracy meets with the other housewives, who say that even if someone moves out, the Commons members always keep in contact and help each other. Bobby goes to see Phil but Debra refuses to let him see her husband. Phil nervously hovers behind the door and refuses to speak. Scott then calls Bobby to let him know the previous owner has disappeared.
On Valentine's day, Bobby returns home to find Tracy waiting with a gift: news that she's pregnant. Bobby is upset that Tracy told Arlene before she told him. Tracy's parents call while Bobby worries. Later, he picks up Tracy at the OB and she shows him the ultra-sound picture. He assures her he's okay with the pregnancy but they're interrupted when Sandra pounds on the car saying someone is chasing her. She runs into traffic, panicked, and is run over. Bobby goes over but everyone else insists she was drunk and committed suicide. He runs back to the car and they go home where Bobby explains that something is wrong and Candace is lying. Turning on the TV, he sees a broadcast of themselves and spots the hidden camera it's transmitted from. They go over to the Fabres but Debra tells them to leave them alone, that they have a daughter. They leave, unaware that Candace is still watching them.
Tracy meets with Arlene, who reassures her that everyone becomes accustomed to the surveillance. Bobby calls Scott and warns that the community will come after them, so they need Meryl's help. Later in their bedroom, Tracy fakes an illness. The next day she fakes a collapse and Bobby picks her up to take her to the doctor. Meryl comes to the house and covers herself over while pretending to be Tracy. The neighbors come over to deliver get-well presents, while Bobby notices that the children are tormenting one of their own, putting a pig mask on her.
Bobby and Meryl wait to hear from Scott, who is getting Tracy and her parents to a cabin. However, Candace storms in and they realize that they've been found out. They try to escape but the community captures them. Candace demands to know where Tracy is, but is astonished that Bobby thinks they want to kill him. However, she notes that their friends and family may start having accidents like Meryl. They give Bobby an injection of truth serum and when he wakes up, they take him to see Tracy. A drunk Phil staggers in and is surprised that Bobby's staying… then takes a pair of scissors and stabs Candace in the neck. Bobby runs outside into the woods and the community chase after him, while the neighbors watch on TV. Bobby finally gets to the road where a car arrives: it's Scott and Tracy. Tracy explains that they came back for him, and Scott says they've got an incredible house in the Commons and they're going to be neighbors. The community residents arrive and take Bobby away.
Several years later, Tracy and her son introduce a new couple to the neighborhood. They ask about her husband Bobby, and she points out that he's upstairs. As Tracy kisses her son, Bobby looks on from the house… trapped in a wheelchair, his legs amputated.