This exciting comedy adventure opens up on a train. Inspector Gadget, his niece, Penny, and their dog, Brain, are on the train waiting for Chief Quimby's orders. The mad conductor works for Doctor Claw.
Quimby arrives with the assignment. Gadget is ordered to protect computer parts from Doctor Claw. Gadget talks to a bird behind bars. The bird leads Gadget on a wild goose chase. Gadget says never trust a bird behind bars.
The conductor, working for Doctor Claw, tries to get rid of Gadget, unsuccessfully as usual. Gadget interrogates the engineer, unaware that he is not a M.A.D. agent.
Soon the train arrives at Doctor Claw's headquarters. The conductor tells Gadget they made it. He sends Gadget to Doctor Claw with some boxes. Claw turns as Gadget comes in. Doctor Claw thanks Gadget for his work.
Gadget steps into the elevator, and Claw plunges Gadget to his death. But Penny battles Claw and saves her uncle. Gadget is all right. Penny re-hijacks the train and gets out.
Later, back at Police headquarters, Chief Quimby tells Gadget he saved the computer parts. Penny tells Chief Quimby that Gadget tricked Doctor Claw by giving him the wrong boxes. The boxes have cat food in them.
On the train, Gadget gives Penny and Brain and everybody at home some safety tips for being on a train. He says not to bother people when they are walking. And if you have to bring your dog, make sure he stays still.