Orphaned Miriam has always been terrified by the sound of THE NIGHT WATCHMAN EXPRESS as it hurtles by her house. The sound of the train gives her nightmares of an underground factory, and a laboratory where brutal experiments take place.
During the day she has very different problems. Her new guardians, the Marchpanes, have arrived with their son, Simon, to live in Miriam's house. The Marchpanes are plotting to take over her dead father's business.
As they are both strong willed and stubborn, Miriam and Simon develop an instant dislike for each other. They have to work together, however, in order to solve the mystery of what the Marchpanes are doing with Miriam's inheritance.
As they come closer to learning the truth, Miriam is kidnapped and put on THE NIGHT WATCHMAN EXPRESS, and Simon must try to rescue her. In doing so, he will have to confront his own parents and the evil forces behind them.
But as he tries to help Miriam, he is captured. Simon is put in a strange, luxurious prison, where his jailers are as hauntingly beautiful as they are dangerous.
As THE NIGHT WATCHMAN EXPRESS arrives at its destination, Miriam comes to the shocking realization that her nightmares about the subterranean factory and the dark laboratory were not just dreams.
What she always feared more than anything is going to come true.
Miriam, who was hiding under the settee in the large living drawing room, looked up from the story she was reading.