aunt. When the children track her down, she admits that she used to be a thief but is trying to forget her old life. At the end of the book, Mrs Hilton announces that Gladys is coming back. She is mentioned a few times in The Mystery of the Missing Necklace. It is unknown what happened to her, as by the beginning of The Mystery of the Hidden House, the Hiltons have a new maid, Lorna. Mr and Mrs Hilton – The parents of Pip and Bets, they are very strict and particular. In The Mystery of the Burnt Cottage, Mr Goon gets the Find-Outers into trouble by complaining to Mrs Hilton. Mrs Hilton is especially described as being "very strict about nice manners." He again complains to the Hiltons when the Find Outers send him a rude message written in secret ink in The Mystery of the Secret Room. Goon persuades the Hiltons not to tell the Find Outers anything about the anonymous letters in The Mystery of the Spiteful Letters. In The Mystery of the Hidden House, Mr and Mrs Hilton forbid Pip and Bets to get mixed up in any mysteries, due to a talk with Mr. Goon. However, despite their shortcomings, the Find Outers look up to and admire the Hiltons. Sid and Perce Goon – (short for Sidney and Percy) Ern's younger twin brothers. They appeared in The Mystery of the Vanished Prince when they went camping with Ern. Sid has an obsession for eating toffee but he soon switches to chewing gum later in the series (according to Ern). Ern also refers to them later about a modelling clay incident (when Sid mistakenly chews Perce's modelling clay as he thought it was chewing gum). Mrs Moon – Cook at the Hiltons during The Mystery of the Spiteful Letters. Hilary – God-daughter of Inspector Jenks, her home (Norton House) is burgled during The Mystery of the Invisible Thief. Luke – The gardener's help next door to Pip and Bets in The Mystery of the Disappearing Cat. Luke develops a close bond with the children, which is strained when he is the prime suspect both times the cat goes missing. It is revealed at the end of the book that Luke was set up to hide the real culprit. It is hinted that his friendship with the children will continue, although he has never appeared or