What does all the magic in the world matter if it can't save the ones you love? It's 1944 Sutton, NY, and Poppy's family owns and runs, Rhyme and Reason, a magical bookshop that caters to people from all different places and time periods. Though her family's world is ravaged by World War II, their customers hail from their past and their future, infusing the shop with a delightful mix of ideas and experiences. The shop runs on a set of rules handed down from one generation of bookseller to the next, with their cardinal rule their most strict: shopkeepers must never use the magic for themselves. But then Poppy's brother's best friend is killed in the war and her brother wants to use the magic to save him. Young Poppy is caught between her love for her brother and loyalty to her family, all the while knowing that her brother's actions could have devastating consequences that reach far beyond the bookshop, feeding an insidious, growing darkness.