With Barney out of town, Andy finds himself in a bit of dilemma. He will have to be out of town for a Sheriff's convention and his replacement has backed out on him. With no one to man the courthouse phones Andy scours the Mayberry phone book. Fortunately (or unfortunately depending on how you look at it) Goober is on hand and offers to fill in. After much consternation and a couple of flat out refusals, Goobers promises to be prompt and responsible work and Andy gives in and agrees to let Goober be his replacement.
The next morning Andy finds out that Goober never showed up (he was supposed to be there at 7:00 am sharp!). He finds Goober in the garage working on Gilly Walker's car. Despite being up to his elbows in carberatour, Goober promises to get to the courthouse as quick as he can. A bit later, Andy calls the courthouse and there's no answer. Instead, he finds Goober still working on Gilly Walker's car on the street in front of the courthouse. Andy gives up and decides to ask Aunt Bee to stay. As he's leaving for the capitol, Goober shows up, tells him Gilly's car if fixed and promises to fulfill his obligation. Andy reluctantly agrees.
A day and a half later Andy returns to Mayberry to find a small crowd huddled around the courthouse doors. He walks in the courthouse and finds Gilly Walker's car sitting in front of his desk. Unable to completely repair the car and unable to diagnose the problem, Goober explains that he began to bring parts the car into the courthouse to work on. That way, he could fix Gilly's car and answer the phones at the same time. Before he knew it, he had taken Gilly's car apart and put it back together in the courthouse!
Despite Andy's rather angry demands that Goober "get this car outta here" Goober manages to get it partially taken apart (Floyd and Gilly keep distracting him). Later that day, Andy finds out that an old friend and the sheriff of a nearby county will be passing through. Desperate not to be the laughing stock of the Sheriff's Associate, Andy races back to the courthouse to find that Goober has put the car back together inside the office. As Andy is desperately trying to disassemble the car, Sheriff Jackson and his deputy walk in. After a few tense moments, Sheriff Jackson concludes that the car in the courthouse is an object lesson, to remind drivers to be careful lest they lose their own car. Andy play's along and saves his reputation.
A little while later Andy bids Sheriff Jackson goodbye. He leads Goober into the courthouse, takes a gun from the rack, sits down, aims at Goober and simply says "Get it outta here."