The book's protagonist is a young woman named Nora Seed who is unhappy with her choices in life. During the night, she tries to kill herself but ends up in a library managed by her school librarian, Mrs. Elm. The library is between life and death with millions of books filled with stories of her life had she made some decisions differently. In this library, she then tries to find the life in which she's the most content. For example, one possible life in which she tries to reunite with her boyfriend and finds herself married to him, but it isn't the way as she expected. She also sees herself as a glaciologist doing research in the Svalbard archipelago in the Arctic – a very different life from the one she tries to escape, but not necessarily a better choice.
