The Simpson family gathers to celebrate Maggie's birthday. After the party, Abe feels depressed, so Marge sets him up for a date with her mother, Jacqueline Bouvier. Eventually, the couple falls in love, which enrages Homer; his argument is that if the pair married, he and Marge would be brother and sister and the children would look like freaks. To impress Jackie, Abe takes her out on the town, but when he does, Mr. Burns steals her from him. Abe is heartbroken. Mr. Burns declares that he is in love with Jackie, and they are going to get married, against both Marge's interest. Meanwhile, Bart buys a $350 Itchy & Scratchy animation cel with one of Homer's credit cards. In order to pay Homer back, Bart blackmails Mr. Burns for $350.
On the day of the wedding, Mr. Burns and Jackie attempt to marry. However, Abe crashes the ceremony and asks that Jackie marry him instead of Mr. Burns. Partly due to Mr. Burns's boorish behavior, she decides not to marry either man. Abe grabs her and they hop on a bus, leaving Mr. Burns lonely. As the bus pulls away from the stop, "The Sound of Grampa" plays on the bus driver's radio. Abe shouts to the driver to turn off the noise, but the driver ignores the request. They both take their seats at the back of the bus to view the departing crowd at the church. The screen fades to black as the ballad of "The Sound of Grampa" continues to play in the background.