Full of regrets, recently unemployed, and grieving the death of her cat Volts, Nora Seed decides to take her own life. In the twilight world between the life and death Nora is surprised to find herself in a library and face-to-face with Mrs Elm, her school librarian from many years before, the person who had told her that her father had died when she was fourteen years old.
The Midnight Library is filled with green books, each one represents a life Nora didn't live in the multiverse. She can pick out any book and find out what her life would have been like if she had made different choices at each of her turning points. There are many possible lives that Nora is given the opportunity to visit. Would she like to be a rock star? a pub owner? a glaciologist? a vintner? What if she had married Dan rather than canceling at the last minute? What if she had just gone on that coffee date with Ash, where would she be now? Is there any world in which Volts is still alive?
Nora also meets other "sliders" - those like her who are moving between lives not lived. Each "slider" has their own guide and space in which to explore their lives. Not all sliders travel via library books - Hugo travels through old VHS tapes in a video store, with his deceased uncle as a guide, for instance.
In the aptly titled chapter "God and other Librarians" the omniscience of Mrs Elm as Nora's guide is made abundantly clear, as is her role as a librarian. She explains to Nora that "The library has strict rules. Books are precious. You have to treat them carefully."
The librarian stereotype is on display as well when Mrs Elm admonishes Nora to "Please be quiet...This is a library".
Ultimately Nora wishes to escape the Midnight Library, especially when she realizes that it is about to self destruct, but how does one do that when there are no doors? Mrs Elm to the rescue: "Who needs a door when you have a book?" she asks.
A new spin on an old theme. Anyone who grew up watching The Wizard of Oz won't be surprised by the ending.