The locomotive called the Rainbow Stone Train runs, not on electricity, but on the energy source called, "Rainbow Stone." Inside, the train is split; from the extremely high class Evening carriage, to the average Afternoon carriage, and finally, to the cheap, but cramped and noisy, Morning carriage. Employed as a crew member of Morning, Toky Towy struggles daily by the side of his strict superior while going through various encounters and farewells again and again.