Nicholas Benedict, a nine-year-old orphan and genius, moves to the Rothschild Manor orphanage after being removed from his previous orphanage, Littleview, because of his narcolepsy, a condition that sends him into deep sleep at unexpected moments, and, in Nicholas' case, often whilst he is laughing or experiencing strong emotion.

Because of his condition, he is forced to sleep in a room all by himself that is locked each night by the director, Mr. Collum, instead of in the dormitory with all the other boys.

He quickly becomes friends with a scarred-faced boy named John, and enemies with the orphanage bullies: Iggy, Breaker, and Moray, or as they are more commonly referred to, the Spiders.

This allows him to wander all around the manor during the night and access many places, which comes in handy, as Nicholas finds out of the legend of huge treasure being hidden in the Manor, and with his friends John and Violet (a deaf girl who lives on a nearby farm),[1] he does his best to find it.

Ms. Candace: The slightly senile nurse, also sneeringly called "Miss Pretty Pills" by Mrs. Brindle.

She lives on a farm near Childs' End and becomes good friends with Nicholas and John through a strange turn of events.