The Mystery of the Missing Man is a part of a very long series of childrens books about a group of kid investigators.Fatty, the leader of the Find-Outers receives news from Chief Inspector Jenks, that a dangerous criminal is on the run, who is also a master of disguise and has an interest in insects. Unfortunately, Fatty is stuck entertaining his father's friend's granddaughter, Eunice. But soon Eunice helps Fatty in solving the mystery. Fatty suspects that the criminal will be in the fair held in the village. Fatty and the others try to investigate suspicious people at the fair such as Bert The clown, Josef, Lucita and their sad grandmother, with a little help from Eunice they find out Josef and Lucita were holding the criminal in their caravan.