The year is 1927, and the Merril children are once again in school but one that's unlike any other. For 10 months out of the year their school, set up in a Northern Ontario railway care that also serves as their home, is on the move. Theirteen-year-old Jenny Merrill loves life on the tracks, but she has a secret wish. She's fallen in love with a violin on page 244 of the Eaton's catalogue. But how will she get the money to pay for it?