Cold Sassy Tree, set in post civil war, Georgia, is about a family that is undergoing a rapid transformation. Told from fourteen-year-old Will's point of view, the story uncovers a family and a small town's reactions to the death of a grandmother and the quick remarriage of the widowed grandfather.

Cold Sassy is the name of the town where Will Tweedy resides. Will's Granny Blakeslee passed away three weeks ago. The whole family is in mourning. This means wearing black dresses for the women and mourning armbands for the men. It means no fishing, reading the comics, or in general, partaking of fun activities. The period of mourning typically lasts a full year. Three weeks into the mourning period, Grandpa Blakeslee gets remarried.

The town of Cold Sassy and the family are shocked at the impropriety of what Grandpa Blakeslee has done. He has married the Milliner, Love Simpson. Grandpa Blakeslee has wanted Miss Love ever since he hired her to make hats in his store in town. He loved his wife deeply, but the romantic side of his marriage had long been dead. When he becomes single, he doesn't feel he can wait the proper amount of time without someone claiming Love.

Grandpa Blakeslee has only one arm. He has never done "women's work" in his life. After his wife passes away, neighbors and his two daughters help care for him. Using this as an excuse, Grandpa Blakeslee asks Love to marry him as a business proposal. If she will take care of him and the house, he will deed the house and everything in it to her.

Love Simpson has given up on love. Once engaged, she was rejected due to the fact that her father had sexually abused her. When Mr. Blakeslee offers her a house, she sees the chance, not only for a house, but for a family as well. It is an offer she accepts.

Love Simpson has been liked by almost all Cold Sassy since she arrived there. Will notes that people like her for various reasons. The men like her because she is pretty and nice. The women like her because she is nice and helps them with fashion. The Methodists like her because she plays the piano well. The only one in town who doesn't like her is Will's Aunt Loma, who is jealous of her.

After Love and Grandpa Blakeslee marry, most of the town shuns her. They see her as greedy, stealing another's man and house. Grandpa Blakeslee's two daughters hate her most of all. They feel she is shaming the family and stealing their inheritance. Will is one of few who still likes her.

Throughout this story, the reader will see how Will deals with the constant strain within the family. He is also dealing with other issues of the process of growing up. Added to these issues are those facing the United States during this time. New inventions, such as electricity, telephones, indoor plumbing and automobiles are all having an impact on the small town. Issues such as discord among race, the North and the South, and the poor and the wealthy, and different religious views are all major factors as Will comes to terms with his evolving role in life.