In 1939, Agatha Christie wrote her most successful novel, one she said was the most difficult to write. It is the story of a madman who invited ten people to spend a holiday on an island off the Devon coast of England. They were lured by either a promise of employment or a chance to meet old friends. The madman's real motive for the invitation was to have them murdered, which occurred. The title of Christie's book was And Then There Were None. The author of The Blue of Portsmouth PD series decided to deviate from writing his own murder plot and instead made the decision to bring Christie's victims from the island off the shore of England and have the murdered in New Hampshire. The Portsmouth PD detectives, led by Madison "Madi" March, were given the challenge to solve the murders. To give the book an authentic Agatha Christie flavor, Madi's addled uncle, Henri Parrot, who believes he is the incarnation of Christie's great detective, Hercule Poirot, is given a badge by Chief Bethany Van Dike and made an honorary sergeant. Surprisingly, Sgt. Henri Parrot has all the detective skills of Hercule Poirot and becomes the leading character of the story.