Three Cousins Detective Club

#15 The Mystery of the Goldfish Pond by Elspeth Campbell Murphy, 1997.
Timothy’s father wants him to sing at his boss’s retirement dinner. The boss’s wife heard Timothy sing once with his choir, and she wants him to sing a special song for her husband at the start of the dinner. His cousins are invited to come along so he won’t be the only kid there. Timothy doesn’t really want to do the singing, but his parents convince him to do it anyway because the boss’s wife is so fond of him and his singing.

Timothy’s father hopes that the dinner will go well because the boss has been worried about the possibilities of competitors getting their hands on information about their new product. Earlier, the boss temporarily misplaced an important memo about it, and he was worried that someone else got their hands on it.
Timothy’s song goes well, and after the dinner, the kids are allowed to walk outside in the garden while the adults listen to a series of speeches. The gardens outside the banquet hall are beautiful, and the kids start to enjoy themselves. Then, they accidentally overhear a couple of adults talking. They can’t quite catch everything they say, but something strange is going on, and something secret is hidden somewhere in the garden.

The theme of this story is Proverbs 11:13, “No one who gossips can be trusted with a secret, but you can put confidence in someone who is trustworthy.”
The book is available to borrow and read for free online through Internet Archive.
My Reaction and Spoilers
The crime that the adults were plotting involves the theft of information. The kids have to figure out the parts of the conversation they couldn’t hear clearly to figure out where the information is hidden. I thought that the clue the children try to figure out was fairly easy. Part of the conversation the kids try to figure out sounds like “-ake -urtle”, and there aren’t many words that sound like “-urtle.”
The boss’s wife seemed eager for the children to go outside, into the garden, and tell her about it later. The kids wondered why she seemed so eager for them to go outside and what she was hoping that they would tell her afterward. It sets the stage for the kids to expect that something unusual or mysterious might happen, which proves to be the case when they overhear the important conversation. The boss’s wife says later that she suspected something might happen because she knew her husband was worried about people stealing company information, and she realized that this dinner would be a convenient place to hand it off to someone.
We never learn exactly what kind of information or new company products the adults were concerned about. We also don’t know exactly who was trying to steal the information or what happens to that person later. The part that the children care about is that they were able to stop the hand-off of the information.