The Listeners by Maggie Stiefvater

"The Listeners" by Maggie Stiefvater is a historical fantasy novel set at the Avallon Hotel and Spa in West Virginia during World War II. The story follows June Porter Hudson, the hotel's general manager, as she navigates the challenges of hosting detained Axis diplomats and an FBI agent investigating them, all while dealing with the magical properties of the hotel's sweetwater springs and the growing tensions of war.