The Find-Outers are pleased to see Ern Goon, along with his two brothers, Sid and Perce, who are camping in a field, next to a school camp. One of the pupils of the school is Prince Bongawah. Days later the Prince disappears and no one knows where or how! This disappearance is just the sort of juicy mystery the Find-Outers love, and with the help of Ern and information from his brothers, they set out to solve the mystery of where the Prince could be. But the clues are rather strange ones! A mother with her twin babies, a baby show, Tiplington Fair, the Find-Outers have really got to use their brains on this mystery, and of course they have to stay one step ahead of Mr Goon!