Out among the farmlands and foothills of the Southern Queensland ranges, something very weird is going on. A vintage steam engine is appearing along the abandoned, isolated railways of the tranquil Mirambeena Valley, where connecting lines no longer exist. The giant locomotive is the very image of the Diablo, which crashed in the region 50 years earlier but the mystery runs deeper - the train is now picking up passengers WHO NEVER RETURN! Enter Tessa Scott, a high-profile city lawyer with a longing for the bush and a passion for helping out people in trouble. As more and more eyewitnesses vanish without trace, and a former university acquaintance goes missing, Tess heads for Mirambeena, looking for clues and answers to the question on everyone’s lips - is the Diablo material ... or ethereal?