Granny is taken home after a morning of shopping by a cab driver, but does not know that his job is to take people home. She thinks when he talks about the $6.30 fare, he is planning to take her to the fair at 6:30. He tells her that she owes him money, and his job is to take people home, getting paid by it. Though Granny thinks he is taking advantage of her. Upset by this, Granny decides to learn to drive.
She has Jethro teach her. They go out on the road a few times, though Granny never improves. The cab driver returns to get the fare that is owed to him, and starts believing he is at a mental hospital.
Meanwhile, Jed has told Drysdale that Granny has gone off driving along with Jethro, and Drysdale sends a report to the police to have Granny escorted back safely. When they return, Granny is told not to drive again. The cab driver, who is still there, tells the police officer what kind of house he is at. The police officer leaves with the promise that Granny will not drive.
In the end, all is well again, until the truck takes off heading for the gate. But this time it is not Granny driving - it is Elly's chimp, Skipper.