There is a murder, and now Will must protect a key that can unlock the train''s hidden treasures. Villians are fast on his heels and strange creatures are lurking outside the windows as the Boundless hurtles across the country. Together with Maren, a gifted escape artist, and Mr. Dorian, a circus ringmaster with amazing abilities, Will must save the Boundless before someone else winds up dead. His adventure may have begun without him knowing . . . but how it ends is up to Will.