Rynn Jacobs is a thirteen-year-old girl who lives in a secluded house that she and her father have rented in a quiet seaside community. But whenever anybody from the town tries to satisfy their curiosity, Rynn's father is never around, and it seems as if the girl is all alone. Rynn's resourcefulness is put to the test as several people try to find out what she might be hiding, including the snobby landlady and her sleazy son.
13-year-old Rynn Jacobs lives alone in a high-class Quebec small town, but unknown to the neighbors, she is leading a secret and dangerous life.
- Rynn (Jodie Foster) is a 13-year-old girl who lives in a semi-isolated cottage near the ocean. We see her preparing a birthday cake for herself, although there is nobody with her to celebrate. She is unexpectedly visited by a man named Frank Hallet (Martin Sheen), and before letting him in, Rynn lights a clove cigarette and blows some of the smoke around the living room. Rynn is uncomfortable with his visit, and we can sense right away that his intentions are predatory. They have an uncomfortable verbal sparring match; Hallet attempts frighten Rynn, and then invites himself into her house. It is Halloween, and he has arrived ahead of his own children, who are out trick-or-treating. Rynn has no Halloween candy to offer, so she cuts them each a piece of birthday cake. Hallet seems to understand something about Rynn's situation; although he comments on the smell of cigarettes and Rynn says her father is upstairs in his study, Hallet makes a number of bold advances on Rynn and touches her inappropriately before leaving. Rynn takes comfort in her hamster, Gordon. Rynn is also visited by a kind policeman, Officer Miglioriti (Mort Shuman). Miglioriti seems genuinely concerned with Rynn, although she gives him the same runaround about her father being indisposed. Miglioriti seems to be aware of Frank Hallet's pedophilia, although Rynn oddly does not mention to him that Hallet has been acting this way toward her.
Rynn's confrontation with Frank is followed up the next day by a visit from his mother, Mrs. Hallet (Alexis Smith). Mrs. Hallet is Rynn's landlady, and her attitude is extremely abrasive. She barges into Rynn's house without asking, and she rearranges furniture in the house as if she lives there. When Rynn's father is not available to speak to her, Mrs. Hallet makes a vague threat about her connections with the school board; she wonders why Rynn is never in school with the other children of the town. It becomes clear that Mrs. Hallet's concerns are not about Rynn's education, but rather the fact that she is in this isolated house alone and her son is making advances toward her. Mrs. Hallet says she wants to collect a case of empty jars that are in Rynn's basement; Rynn refuses to allow her to go into the basement and tells her to come back later for the jars.
After this confrontation, Rynn goes to the town and looks up public records at the library, and she discovers that Mrs. Hallet was lying about her connections to the school board. Rynn sees Frank again in town, but Frank is frightened away by the sudden appearance of Miglioriti. The policeman gives her a ride home and they have a friendly conversation; Miglioriti comes to understand that Rynn is much wiser than her actual age. She speaks a number of languages and has a level of cunning and awareness that would normally belong to an adult.
When Mrs. Hallet returns to collect the jelly jars, she demands to speak to Rynn's father. Rynn refuses and says her father is out. This time Rynn is blunt with Mrs. Hallet, indicating that she will not be intimidated by the woman and that she knows she is simply protecting her pedophile son. Mrs. Hallet is enraged, especially when Rynn tells her that she knows she lied about the school board. Mrs. Hallet goes to leave and realizes that the jars do not have any lids; Rynn forgot them in the cellar. When she heads toward the cellar, which is accessed by a trap door in the floor, Rynn becomes panicked and screams at Mrs. Hallet to get out. Instead, she pushes her way past Rynn and goes into the cellar. From the basement, we hear her scream and she rushes back upstairs in terror, but she knocks the door loose and it crashes down on her head. Rynn looks down and sees Mrs. Hallet lying on the cellar steps, dead.
Rynn attempts to cover up the evidence of Mrs. Hallet's visit; she hides her umbrella and tries to start her car to move it. The car won't start, and it attracts the attention of Mario (Scott Jacoby), a boy who is passing by on a bicycle. Mario is around Rynn's age, and he is on his way to a birthday party where he is to perform magic tricks. Mario is a gentle young man who walks with a cane due to an instance of polio in his childhood. Mario promises to help Rynn later, and he returns later to help her hide the car. Rynn makes him dinner, and when his uncle drops by to check on Rynn, Mario tells him Rynn's father was there but has gone to bed. Rynn is grateful that Mario has helped her keep the illusion going, although she doesn't open up to Mario right away about the reasons for her deceitfulness.
Frank Hallet also shows up that night and interrupts their dinner; he is looking for his missing mother. Rynn refuses to discuss it with him, even though he kills her hamster by burning it to death with a cigarette. He also humiliates Mario, until Mario suddenly turns on him by revealing a knife hidden inside his cane. Frank runs off, but it is clear he will return.
Rynn then tells Mario her secrets. She allows him to go into the cellar and he sees the corpses of both Mrs. Hallet and Rynn's mother. Rynn explains that her father was terminally ill, and that he was concerned about Rynn's estranged mother showing up to collect her if it became known that he was dead. Rynn and her father conspired to make sure that his death would be as inconspicuous as possible; Rynn's rent is paid for the next three years, and her funds are secured in a safety deposit box in the local bank. Almost every aspect of her existence is accounted for, and the only variable was her mother. Rynn's father gave Rynn a vial of white powder and told her to put it into her mother's tea if she ever showed up looking for her. It was cyanide, and Rynn began to suspect this even before her mother collapsed and died. Afterwards she hid her mother's body in the basement.
Mario seems to understand and accept Rynn's situation, and he becomes her co-conspirator. He helps Rynn to bury the bodies outside the house, but catches a serious cold in the process. Later Rynn is visited by Miglioriti again, and he is on the verge of exposing Rynn's lies about her father. Suddenly Rynn's father appears and talks to Miglioriti, who is now embarassed that he ever doubted the man's existence. Miglioriti doesn't know that he is actually talking to Mario, who is wearing a disguise including a rubber mask. Miglioriti leaves, satisfied that Rynn's father will take care of any further problems.
Mario's condition worsens, and he is hospitalized for pneumonia. Rynn visits him but he is sleeping and cannot hear her. She now understands that even though she has tried to be entirely self-sufficient, she has come to depend on Mario.
When Rynn returns home, she is confronted by Frank Hallet, who has emerged from her own basement, giving her quite a shock. Hallet still suspects that Rynn is responsible for the disappearance of his mother because he has found one of his mother's hairpins, and half of a bright red fingernail in the cellar. Frank seems to not really mind that his mother is gone, and he implies that he will use this information to blackmail Rynn into a sexual relationship with him.
Rynn now knows what she must do. She offers to fix them some tea, and she puts cyanide into one of the cups. Before they drink, Frank becomes suspicious and makes Rynn drink the cup that was meant for him. Rynn, however, is too smart for that: she herself had taken the poisoned cup, knowing that Frank would switch them. Frank drinks the tea and Rynn watches as the cyanide kills him.