Kate and her younger brother Tom lead dull, uninteresting lives. And if their dull, uninteresting parents are anything to go by, they don't have much to look forward to. Why can't Kate have thrilling adventures and save the world the way people do in books? Even her 11th birthday is shaping up to be mundane -- that is, until her mysterious and highly irresponsible Uncle Herbert, whom she's never even met before, surprises her with the most unexpected,...

Kate and Tom are now full-fledged conductors of the steam-powered, animal-saving Great Secret Intercontinental Railway, but when Kate takes the Silver Arrow out on an unsanctioned mission to find Uncle Herbert she discovers a mysterious train called the Golden Swift with an agenda of its own.