Grampa Simpson falls in love with Beatrice Simmons, a fellow resident of the Springfield Retirement Castle. During the course of their brief romance, Bea passes away and leaves Grandpa her entire savings, $106,000. Grandpa formulates to give the money to charity but he can't choose which one is worthiest, but when he is unable to make the perceptive choice, Grampa goes to a casino to gamble it away.
In a month's time, Grandpa plans to present Beatrice with a present on her birthday. However, Homer comes for their monthly outing with Grampa, who explains that he can't go, as it is his girlfriend's birthday. Homer thinks this is just Grampa behaving in a cranky manner and not wanting to come for pleasure. Grampa is taken along with the family to Discount Lion Safari. At the refuge, the family's car gets stuck in the mud and, to make matters worse, hungry lions begin circling the car, trapping the family in the car overnight. After a hunter helps run the lions off the next morning, Grampa returns home expecting to visit Bea. However, Homer pulls up just in time for an ambulance to drive off. It turns out that Bea had died of a burst ventricle when Grampa was out with the family.
Grampa is saddened by these events, but mentions that Bea must have cared for him, in that she didn't request that he be a pallbearer at her funeral. Homer tries to explain how sorry he is, but Grampa is too nettled to listen. Blaming Homer for making him miss the final precious moments of Bea's life, he vows not to forgive Homer and disowns him as a son.
Shortly afterwards, Grampa is visited by Lionel Hutz, the executor of Bea's estate. It turns out that Bea was a wealthy widow, and left an inheritance of $106,000 to Grampa. Bea's stipulations say that Grampa can enjoy this money any way he sees fit. He tries everything from buying a fez (which is claimed to have belonged to Napoleon), to going to an amusement park, but none of these alternatives make him happy. While on the roller coaster at the park, Bea appears to Grampa in the form of a poltergeist, telling him that if the money isn't helping him, it should go to those who it could benefit.
Also at Bea's request, Grampa goes to visit the Simpsons, and forgives Homer. While having dinner, Grampa announces his intentions to donate Bea's money. He plans to have people come talk to him, and then he will choose who is in most need of it. This announcement soon gains local media attention, and a line forms for people to make requests of Grampa for the remaining money (even reporter Kent Brockman reports on this, then gets in line).
After a number of interviews, Grampa still hasn't chosen a good person willing to gain possession of the fortune, so he goes for a walk to clear his mind, and notices the plight of the Springfield homeless and realizes it wouldn't be enough money to help everyone who needs it most. At a suggestion by Jasper, he goes on a senior citizen gambling trip, with the possibility that he could double or triple the remaining funds. When Homer finds out about this, he rushes to stop Grampa, and succeeds when Grampa almost loses the money in a game of roulette.
Outside the casino, Homer asks Grampa if he has figured out what to do with his inheritance. Looking at his hands, Grampa explains that he has. With the inheritance, Grampa helps renovate the retirement home, and has the dining room named in Bea's honor.