In the charming town of Riverton, Ohio, John Brown lives with his niece, Penny, and her devoted dog, Brain. Although he dreams of becoming a police officer, he currently serves as a security guard at the renowned Bradford robotics laboratory. Under the mentorship of Artemus Bradford and his daughter Brenda, they strive to develop advanced projects, including the revolutionary Gadget Program, which aims to integrate android officers into local law enforcement.
However, chaos ensues when Sanford Scolex, a morally dubious entrepreneur, breaches the laboratory with a robotic tank, leading to the shocking theft of a lifelike robotic foot and the brutal murder of Artemus. In a desperate attempt to stop him, John pursues Scolex's limousine in his trusty hatchback, only to find himself slipping on an oil slick that Scolex had strategically laid down. This results in a dramatic crash, leaving John's car in shambles and him presumed dead. Little do they know, a cosmic twist of fate leaves Scolex injured when a bowling ball from the explosion crushes his hand.
In a remarkable turn of events, Brenda chooses to revive John, utilizing him as the inaugural experiment for the Gadget Program. She outfits him with a selection of gadgets, gives him the new identity of Inspector Gadget, and implants a control chip to enhance his capabilities. Initially, John's encounters with these high-tech tools are fraught with comedic mishaps, but he gradually learns to navigate his new abilities with assistance from the clever Gadgetmobile, a talking robot car equipped with advanced AI.
As John grapples with mastering his gadgets, he inadvertently thwarts two car thieves, earning a small yet significant victory. Meanwhile, Brenda invites him to work in her lab, unaware that Scolex is plotting to steal her groundbreaking ideas. Simultaneously, Chief Quimby dismisses John's claims regarding the murder investigation, relegating him to trivial chores.
Frustrated by this dismissal, John embarks on his solo investigation and uncovers a key piece of evidence—a scrap of metal connected to Scolex. With Penny's help, he pulls together the clues, setting off an exhilarating game of cat and mouse with his adversary. When Scolex constructs his own android, Robo-Gadget, using Brenda's research, he unleashes chaos in Riverton, framing John for his misdeeds with a series of cunning pranks.
Despite being captured and disabled when Scolex damages his control chip, John remains a key player in this conflict. Meanwhile, Brenda faces her robotic lookalike, Robo-Brenda, who divulges the shocking truth about Scolex's intentions and the tragedy of her father's death. United in purpose, Brenda, Penny, and Brain rally to find John, who is eventually awakened from his stupor by a kiss from Brenda.
As the tension escalates, John and Brenda deepen their bond and join forces to confront their nemesis. A high-octane chase ensues involving Claw and Robo-Gadget in a dramatic battle on a precarious bridge. Ultimately, John triumphs, severing his android opponent's head in a spectacular showdown.
The action cranks up further as they outwit Scolex in a relentless game of pursuit. Brenda is captured, prompting John to leverage his trusty helicopter hat for a daring rescue against Claw's aerial assault. The climax unfolds atop Scolex's skyscraper, where John showcases his ingenuity and resourcefulness, neutralizing Scolex's claw in a fierce confrontation.
Together, they narrowly escape, landing safely on the bustling streets of the city with the aid of Brenda's cherished parasol. Once Scolex is captured, John is celebrated as a hero as the authorities arrive just in time to take the villain into custody. In a twist of fate, Penny returns alongside Quimby and a reformed Sykes, who reveals Scolex's crimes.
The film wraps up with John and Brenda embarking on a romantic adventure, cruising through the lively streets in their beloved Gadgetmobile, as they chase the allure of a teasing red car ahead.
