More Perfect than the Moon (Sarah, Plain and Tall, 4)

The fourth book in the series that began with the Newbery Medal-winning Sarah, Plain and Tall by Patricia MacLachlan.
I am a watcher. I am a listener, too. I am invisible. I can make myself so small and quiet and hidden that sometimes no one knows I am there to watch and listen.
Cassie spends her days watching Grandfather and Caleb in the barn, looking out at Papa working the fields, spying on her mother, Sarah, feeding the goslings. She’s an observer, a writer, a storyteller. Everything is as it should be.
But change is inevitable, even on the prairie. Something new is expected, and Sarah says it will be the perfect gift. Cassie isn’t so sure. But just as life changes, people change too. And Cassie learns that unexpected surprises can bring great joy.