In Los Angeles, Lois Cavendish, a member of the hotrod club the Zeniths, accepts a challenge to race in the dry river bed against outsider Nita. When a policeman notices the girls racing, he intervenes, but Lois roars away, unaware that Nita has skidded into a wall. Back at the Zeniths’ garage, the club’s leader, Stan, introduces members Dave, Rhoda, Bonzo, Tommy and Amelia to journalist Tom Hendry, who is researching an article on teenagers. Impressed by Tommy’s detailed description of a car he has designed and built, Hendry asks whether the reputation of hot rodders as delinquents is true. Stan and the others laugh at the suggestion, but Stan reveals that the Zeniths are unusual in that they have rules that include no rumbles or “chicken” road races because their priority is working on cars. Joined by Lois, the Zeniths take Hendry to a café where several of their members sing in a rock and roll band. Stan explains to Hendry that the Zeniths hoped the band would earn enough money to allow them to pay rent on the garage, but unfortunately they have not earned enough and must vacate the garage in two weeks. During the evening, Nita, her boyfriend Tony and members of their gang arrive at the café, angry over Lois’ behavior after the race. Stan insists that the Zeniths will not be goaded into a fight and orders Tony to leave. Later, Stan drives Lois home where her father Wesley expresses his concern that Lois’ obsession with cars is unnatural for a young woman. Lois assures her father that she is happy, but Wesley shows her a newspaper article describing her race with Nita and her near-serious accident. Stating that one of his most important clients, the elderly eccentric Anastasia Abernathy, will be spending two weeks with them, Wesley regretfully tells Lois he must ground her for that period. Lois accepts her punishment, but asks Wesley and her mother Alice if she might have a party for the Zeniths at the house, and the Cavendishes reluctantly agree. Anastasia arrives soon after with her pet parrot Alfonso, who is able to speak and mimic unusual sounds. A few nights later, the Zeniths party enthusiastically at the Cavendish home and are happy to include Wesley, Alice and Anastasia in the revelry. Nita, Tony and their gang attempt to crash the party and Lois, fearing a brawl, agrees to dance with Tony. When Stan threatens Tony, Alfonso imitates the sound of a police siren and Tony and his gang flee. Several days later, Anastasia visits the Zeniths’ club on their last day at the garage. Dismayed that the teens have no alternative place to go, Anastasia recalls her old family home, Dragstrip Hollow, which was abandoned when it was discovered to be haunted. Stan asks Anastasia if they might use it for their club headquarters if they can rid the house of its ghosts and the old lady agrees. The Zeniths, accompanied by Hendry and Anastasia, go to Dragstrip Hollow that night and despite hearing unusual shrieks and thumps, bravely settle in for the night. The lights go out soon after the group arrives and they are forced to light several candles. While Lois sits against the fireplace, she abruptly is whirled into another room, before ending up back in the living room. As the Zeniths begin dozing, most are unaware of a weird, monster-like figure, who has been hiding behind the fireplace, moving around the room. The next morning, Anastasia admits that since the Zeniths appear to have conquered any ghosts, they may have use of the house. The teens spend the day cleaning the house in order to throw a party that evening to celebrate their new club. That night, the Zeniths hold a “spook” party, where everyone dresses in costume. Tony and Nita arrive and are allowed to join in the party. Later, Stan and Hendry finish exploring several rooms, but remain unable to explain the continuing strange shrieks and knocking sounds. When Lois returns from a race, Stan chastises her for breaking club rules and after she promises to pay the club fine and to tell her father, Stan forgives her. Downstairs at the party, Dave unveils his latest car which he describes as a thinking car. Anastasia scoffs at the notion, but Dave has her sit in the car and give it a spoken command. The group is impressed when the car starts upon request and when Anastasia asks if there is a ghost in the house, the car drives toward the fireplace and presses a button, revealing a hidden room behind it. Stan orders everyone to remove their costume masks and when one figure, disguised as a monster, refuses, Stan and the others force him to take off his mask. Hendry recognizes the man as a former movie extra who frequently played monsters in low budget films. The man admits that the end of his career had made him despondent and he wanted to cling to his only talent by haunting the house. After his confession, the man abruptly flees and the party resumes minutes later. A little later, Anastasia sees the ghost of her uncle John exit from his portrait and, disturbed by the rock music, disappear into the night.