“That’s not a bad idea,” said Larry. “If we could get Clear-Orf on to the track of a false mystery, he wouldn’t spend any time or attention on our real one. So, if we do find he’s snooping around, following us, or making inquiries, we’ll present him with a first-class mystery - that we’ll make up for him ourselves!”

This seemed a fine idea. It didn’t occur to any of the children to take Mr. Goon into their confidence and let him work with them. He disliked them so much, and was such a blunderer, that if any one was to be told, they preferred to tell their friend, Inspector Jenks - the “very high-up policeman” as Bets called him. He would listen to them with attention and interest, and would certainly not take any credit that was due to them. Clear-Orf, they knew, would pooh-pooh anything they did, and pretend that he had done all the brainwork.

But he was a suspicious fellow, and if he thought they really were at work on some mystery again, he would certainly try to interfere. The children felt terribly excited when they thought of this new mystery. They had so much enjoyed their first two mysteries - now here was another - and a very peculiar one too.

“Let’s see,” said Fatty, considering. “I think the first thing to do is to find out who the house-agent is, as I’ve said, and try to get the keys. Then we could explore that room and find out if possible what it’s for and why it’s fully furnished.”

“Right,” said Larry. “You can tackle the house-agent tomorrow, then. You’re good at that sort of thing. But if you manage to get the keys out of him, I’ll be surprised!”

“You wait and see,” said Fatty, who now had such a high opinion of himself that he thought nothing was impossible. He could already see himself at the head of all the British Police, the most famous solver of mysteries the world had ever known.

Nobody seemed to want to play a game. The thought of the new mystery made them feel unsettled and excited.

“Do you think it will be a dangerous mystery?” asked Bets rather anxiously. “The other two we did weren’t dangerous. I don’t think I’d like a dangerous mystery.”

“Well, if it is dangerous, we three boys will tackle it,” said Fatty rather pompously. “And you two girls must keep out of it.”

“I certainly shan’t!” said Daisy indignantly. “Bets can do as she likes - but I’m sharing this mystery from the beginning to the end, Fatty. I’m as good as you boys any day.”