Karon continues developing many characters that she created in At Home in Mitford, including Father Tim, Cynthia, Dooley, and Miss Sadie. She adds Buck Leeper and Meg Patrick and expands the role of Edith Mallory.

Father Tim is a sixty-three-year-old bachelor, the rector of Our Lord's Chapel. A diabetic, he diets and exercises regularly, so he is physically stronger than he was in the first novel, At Home in Mitford. His spiritual life is not as evident in A Light in the Window as it was in the first book. He is more involved with secular concerns. Father Tim discovers that he must not only make a commitment to God, but also to people he loves.

Cynthia Coppersmith is a charming woman, pretty, petite, fun-loving, affectionate. Father Tim's family and friends urge him to marry her, but he procrastinates and nearly loses her. She has a successful career...