Plot

Peter runs a New York tour. Christine is a recently widowed art gallery owner, and she falls in love with him. But, her 10-year-old son loves her way too much and has an unhealthy and pathological attachment to his mother.

Peter is a wacky free spirit who runs a New York tour specifically for New Yorkers. Christine is an uptight art gallery owner, recently widowed, who is stepping back out into the dating world. He pesters her into going out with him and, since she cannot perceive the difference between obnoxious behavior and charm, she falls in love with him. There's a problem, though. Her 10-year-old son, Jamie is a loonball. He loves her way too much, and has an unhealthy and pathological attachment to his mother. After she remarries, his rage and misery overwhelm him and he plots to kill his stepfather.

Since her husband's death two years earlier, Christine 'Chris' Sutton (Joan Hackett) has divided her time between running her art gallery in New York City and rearing her precocious ten-year-old son Jaimie (Scott Jacoby), who has developed an unhealthy fixation on his mother.

One night, Chris has a dinner date with a man, and over Jaimie's objections, insists that Mary (Jeanne Tanzy Williams), a high-school student living in the area, come to babysit while she is gone. Jaimie, who has an extremely high I.Q., is involved in making two movies: one an improvisational film at school, the other a more personal film of home-movie footage shot by his late father. Once Jaimie goes to bed, Mary greets her boyfriend Phil (Frank Fiore), and as the teenagers begin to kiss, Jaimie enters the room and asks Phil if he is a virgin. After the flustered Phil makes an abrupt departure, Jaimie pontificates about acceptable sexual relationships, impressing the naïve Mary with his knowledge. When Chris returns home with her date, Jaimie hostilely orders the man to get out. Upset by Jaimie's behavior, Chris meets with a child psychologist (James Karen) to discuss the possibility that her dating may be harming her son.

While out walking one day, Chris is stopped by Peter Simon (Robert Kline), a free-spirited, whimsical tour guide who badgers her into climbing into his beat-up van for a tour of the city. As they drive past the art galleries of the Upper East Side, Chris mentions that she is an art dealer, but refuses to tell Peter her name or address.

Some days later, Peter arrives at Chris's gallery with a group of tourists and confides that he has already visited five different galleries looking for her. Over coffee, Peter directs Chris to meet him in front of the art gallery the next afternoon. When she stands him up to play a game of Scrabble with Jaimie, Peter phones and threatens to come to her house unless she meets him at the gallery. Lying to Jaimie that she is going to see a client, Chris hurries to the gallery where Peter is waiting with his van. As they drive through the city, he invites strangers to an impromptu party, and at the end of the evening, drives Chris to a road along the river where he lives in his van. After discovering their mutual love of Greece, Peter ingenuously asks Chris to make love, and disarmed, she agrees.

Afterward, to assuage her guilt about lying to Jaimie, Chris showers him with gifts. Suspecting that something is amiss, Jaimie bribes Mary to turn Chris down the next time she calls to offer a babysitting job. One night, when Chris tells Jaimie that she has a "business appointment" but Mary is unavailable, Jaimie convinces her to leave him alone while she goes out. After she departs, Jaimie goes to see Tony (Randy Digeronimo), a juvenile delinquent he met in the park, who has agreed to give him a ride on his motorbike in return for Jaimie's advice on the best way to rob a gas station.

As Chris and Peter stroll down the street, Jaimie surreptitiously follows, filming them as they stop in a doorway and kiss. Later, Peter asks Chris why she refuses to let him accompany her home, and she finally tells him about Jaimie. Soon after, Chris tells Madge (Phoebe Dorin), her partner in the art gallery, that she is in love with Peter, and later invites him home to meet Jaimie. When Jaimie treats Peter with condescension, Chris chastises her son for his lack of respect, but after Jaimie becomes upset, she promises never to see Peter again, even though she loves him and he has asked her to marry him.

After Chris assure Jaimie that she can love them both, Jaimie relents, but at the wedding, he steals the wedding ring that Peter is to give Chris then later throws it away. After the happy couple return from their honeymoon to regale the glum Jaimie with funny stories, Peter buys a new tour bus and lands a lucrative contract with the city.

One night, Jaimie awakens screaming from a nightmare and insists on sleeping with his mother for comfort. As Jaimie demands increasingly more of her attention, Chris, blaming herself for his regression, once again visits the psychologist for advice.

On the day before Chris and Peter are planning to go away for a weekend vacation, Jaimie returns from school after being beaten up in the park by Phil, who still holds a grudge against Jaimie for humiliating him in front of Mary. Concerned about Jaimie, Chris decides to cancel the trip, angering Peter. In a heated argument, Chris orders Peter to get out, after which he packs his bags and leaves.

Two weeks later, Peter, drunk, sneaks into Chris's room through the fire escape and forces her to have sex with him. Their rough lovemaking ends in Chris's sighs of pleasure as Jaimie listens from the other side of the bedroom door. Jealous, Jaimie decides to make a pornographic film with the willing Mary. After having Mary undress, Jaimie begins to lecture her about the intricacies of sexual titillation, but when she eagerly encourages him to have sex with her, he discovers that he cannot and runs away in tears.

Traumatized, Jaimie wanders the city and is picked up by the police while standing on some subway tracks. The police later release Jaimie into Peter's custody, after which the boy pleads with him not to tell Chris about the incident and offers to "pay him back" for his silence.

One night, Chris and Peter decide to watch Jaimie's unfinished home movie, and when they see the footage that Jaimie secretly shot of them, Chris, frustrated by Jaimie's domination of her life, decides to send him to summer camp. Even though Peter thinks summer camp is a bad idea, Chris insists and tells Jaimie that the opportunity to go to camp is a "gift" from Peter. Thinking that Peter originated the idea of his going to summer camp, Jaimie decides to get even.

On the evening that Jaimie is to leave for camp, he rigs the apartment to burst into flames when Peter returns from driving him to the bus station. At the station, Jaimie claims he has suddenly remembered that a client called to set up an appointment with Chris. Realizing that the appointment is within 15 minutes, Chris races out to meet the client. Once Peter has waved goodbye to him, Jaimie slips off the bus and is picked up by Tony who drives him back home. Becoming concerned when Jaimie scrambles up the fire escape and implies that he is going to commit murder, Tony decides to find Chris. As Peter opens the door to the apartment, Jaimie ignites the fire, then slips into the room adjoining the fire escape and locks the door, thus barring Peter's escape.

Meanwhile, Tony locates Chris and warns her about Jaimie. Bursting into the blazing apartment, Chris finds Peter unconscious on the floor and cradles him in her arms. As neighbors clamor at the door to help carry Peter out of the flames, Chris's coat catches fire. From the locked room, Jaimie listens to his mother's dying shrieks as she burns to death.

Some weeks later, Peter comes to visit Jaimie at the psychiatric clinic at which he has been committed. While the nurse consults with Peter about Jaimie's condition, the boy stares blankly from an upstairs window.