In turn-of-the-century London, Roberta 1Bobbie2 Waterbury lives a perfect upper-class life with her parents, sister, and brother until one fateful night when her father is mysteriously arrested. Suddenly impoverished, the children and their mother are forced to move to a dusty cottage far away in the country perched on the edge of a railroad. But along these magical tracks, in the nearby station and on the mighty trains themselves, Bobbie and her siblings will discover adventure, face danger, and forge friendships that will change their young lives forever.