The protagonist, Nora, is talking with Mrs. Elm about her past and how she had always tried to impress others.
Nora was always felt that she was living in her brother's shadow, and felt pressured to live up to her parents' and sibling's expectations.
She recalls trying to earn her brother's approval by learning to play the piano after he refused to, and how she spent her money on piano-teaching guides and Mozart for Beginners and The Beatles for Piano.
Nora recognizes every life she had tried so far in the library had been someone else's dream. The dreams of married life, a trip to Australia, becoming a swimming champion and becoming a glaciologist all belonged to others.
Mrs. Elm advises Nora to choose more lives from the bottom or top shelves. These are lives she could live but never dreamed of, the less obvious lives.
They discuss the concept of choices and Nora remembers studying Aristotle and his philosophy that excellent outcomes are the result of wise choices from many alternatives.
Nora and Mrs. Elm play a game of chess, discussing the countless possibilities that each move opens up. Mrs. Elm tries to explain that life is much like a game of chess, where every hope, regret, and moment of living is based on possibility.
Nora wins the game of chess and feels a bit better. She decides she wants to lead a gentle life working with animals, the kind of work she enjoyed and chose to do in her school days instead of aspiring to work in String Theory.
Mrs. Elm repeats the advice she gave earlier, 'Never underestimate the big importance of small things', which proves to be useful.