Good Night, Mr. Tom is about a young boy named William Beech who is evacuated from London at the beginning of the war to a safer rural village called Little Weirwold. Nine-year-old Willie is the only child of an abusive, over-religious single mother. We learn that his mother will not allow him to be evacuated unless he can stay with someone "who is religious or who lives near a church."

Tom Oakley, 60-some-year-old caretaker of the local village church and cemetary, is a cranky, embittered old man who ends up with Willie. It soon becomes clear to old Tom that Willy's life in London was very different. Like many children from poor London neighborhoods, Willie is suddenly exposed to a whole new life in Little Weirwold. He has never seen a cow before, nor picked blackberries, nor slept in a real bed. He knows nothing about fresh milk, squirrels, garden dirt, horses, riding a bicycle, swimming, or even petting a dog. Timid Willie has no friends and cannot read.

We learn through the course of the book about Tom's life as a young man and the tragedy of his beloved wife Rachel. His gruffness begins to fall away as he and his little dog Sammy help Willie learn to read and to heal. Willie begins to live life as a normal boy with Tom's kindness and his newfound friend, Zack, a fellow evacuee who is Jewish. Willie makes friends, and his talent for drawing and painting begins to blossom. He becomes a part of life in Little Weirwold. It's a happy life, in spite of the outbreak of war.

Reading this book is like stepping back into pre-World War II rural England, complete with thatched cottages, heavy country accents, and hard-working, thrifty villagers.