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 world is ravaged by World War II, customers hail from the past and the future, infusing the shop with a delightful mix of ideas and experiences.

Poppy dreams of someday becoming shopkeeper like her father, though her older brother, Al, is technically next in line for the job. She knows all of the rules handed down from one generation of Bookseller to the next, especially their most important one: shopkeepers must never use the magic for themselves.

But then Al's best friend is killed in the war and her brother wants to use the magic of the shop to save him. With her father in the hospital suffering from a mysterious illness, the only one standing between Al and the bookstore is Poppy. Caught between her love for her brother and loyalty to her family, she knows her brother's actions could have devastating consequences that reach far beyond the bookshop as an insidious, growing Darkness looms. This decision is bigger than Poppy ever dreamed, and the fate of the bookshops hangs in the balance.