In this stunning middle-grade fantasy debut, a clever girl joins a crew of trolls aboard an impossible train. Suzy Smith believes in science. Then the Impossible Postal Express comes roaring through her living room and her world turns upside down. After sneaking on board, Suzy suddenly finds herself Deputy Post Master aboard the train, and faced with her first delivery—to the evil Lady Crepuscula. Then, the package itself begs Suzy not to deliver him. A talking snow globe, Frederick has information Crepuscula could use to take over the entire Union of Impossible Places. But when protecting Frederick means putting her friends in danger, Suzy has to make a difficult choice—with the fate of the entire Union at stake. Hand to fans of Serafina and the Black Cloak and The School for Good vs. Evil.