The story could center on the process of selling the grandparents' house. It may involve the realtors coming in and assessing the property. There could be a lot of memories tied to the house that the characters in the story have to deal with as they prepare it for sale. For example, finding old family photos in the attic or remembering special events that took place in the different rooms of the house. The sale might also bring in new characters, like potential buyers who have different ideas for the house, which could create some conflict or interesting interactions.
Perhaps the main plot is about the discovery during the selling process. As they start to clean out the house in preparation for the sale, they find hidden secrets. It could be a long - lost letter from a relative, or some old heirlooms that have a mysterious past. This discovery might change the family's perspective on the house and the sale. They might start to question if they really want to sell it, or it could make them more determined to sell it quickly if the discovery is something negative or brings up old family problems.