This conclusion of the Sarah, Plain and Tall stories gathers the whole cast of characters for a prairie wedding. Changes in the family are reflected in the changing times; Papa goes to town to buy a car to transport his guests. Fourth-grade Cassie narrates the tale of welcoming the relatives and preparing the celebration for her sister, Anna. But her focus isn't on the bride and groom.

Partly, she ponders why people would want to get married; her dream companion would be one of her dogs. She closely observes Grandfather and Jack, the oldest and youngest members of the family. Their special bond shows up in the way Jack talks, walks, and behaves like Grandfather. Cassie observes how Grandfather is preparing for death. Even the sad ending highlights the story's overall theme of family ties as they weave through generations.