The Five Find-Outers, Bets, Pip, Daisy, Larry, Fatty and Fatty's dog, Buster, with the help of next door's gardening boy, Luke, try to find out where Lady Candling's prize Siamese cat has gone. It seems that Luke is the chief suspect but the children are sure that he wouldn't have stolen the cat.
They have their own suspicions, however - why is Mr Tupping, Lady Candling's gardener, so unfriendly and why won't Mr Goon, the local policeman, listen to them?