“Well, I bet you were bottom of the form then,” said Larry. “You can’t do that sort of thing and work, too.”

“I can,” said Fatty. “I was top of the form in everything. I always am. You won’t believe my maths marks - I only lost -”

“He’s off again,” said Pip to Larry. “He’s like a gramophone record, isn’t he?”

Fatty subsided and glared at Pip. “All right,” he said. “Say what you like - but I bet you don’t know how to do invisible writing, or get out of a locked room when the key isn’t your side!”

The others stared at him. “You don’t know how either,” said Pip disbelievingly.

“Well, I do then,” said Fatty. “Those are two of the things I’ve learnt already. And I could teach you a simple code, too, a secret code.”

This sounded exciting. Bets stared at Fatty with eyes wide.

“Teach us all those things,” she begged. “Oh, Fatty, I would so like to do invisible writing.”

“You have to learn the art of disguising yourself too.” said Fatty, enjoying the rapt attention of the others.

“What’s disguising?” asked Bets.

“Oh, dressing yourself up in such a way that people don’t know it’s you,” said Fatty. “Putting a wig on and perhaps a moustache or different eyebrows, wearing different clothes. For instance, I could disguise myself quite well as a butcher’s boy if I had a striped apron, and a knife or something hung down from my belt. If I wore an untidy black wig too, I bet none of you would know me.”

This was really too exciting for words. All the children loved dressing up and pretending. This business of “disguising” seemed a glorified dressing-up.

“Are you going to practise disguising yourself next term?” asked Bets.

“Well - no, not in term-time,” said Fatty, thinking that his form master would soon see through any disguise. “But I thought I might these hols.”

“Oh, Fatty! Can we too?” said Daisy. “Let’s all practise being proper detectives, in case another mystery crops up. We could do it much better then.”

“And if another mystery doesn’t crop up, we’ll have the fun of practising for it anyway,” said Bets.

“Right,” said Fatty, “but I think if I am going to teach you all these things I ought to be the head of the Find-Outers, not Larry. I know Larry’s the oldest - but I think I know more about these things now.”

There was silence. Larry didn’t want to give up being head, though in fairness he had to admit that Patty was really the cleverest at spotting things when they had a mystery to solve.

“Well, what about it?” said Fatty .“I shan’t give away my secrets if you don’t make me head.”

“Let him be head, Larry,” said Bets, who admired Fatty tremendously. “Head of the next mystery anyway, whatever it is. If he isn’t as clever as you at solving it, then we could make you head again.”

“All right,” said Larry. “I do think Fatty would make a good head, really. But if you get conceited about it, Fatty, we’ll sit on you hard.”

“You needn’t tell one that,” said Patty, with a grin.

“Right-o! I’ll be head. Thanks, Larry, that was sporting of you. Now I can teach you some of the things I know. After all, you simply never know when they might come in useful.”

“It might be very, very important to be able to write a letter in invisible ink,” said Bets. “Oh, Fatty, do teach us something now.”

But Bets’ mother just then put her head in at the playroom.

“I’ve got tea ready for you downstairs. Wash your hands and come along, will you? Don’t be too long, because the scones are nice and hot.”

Five hungry children and an equally hungry dog shot off downstairs, forgetting everything for the moment but hot scones, strawberry jam, and cake. But they wouldn’t forget for long - things sounded too exciting!

Christmas came so quickly, and there was so much to do that Fatty had no time to teach the Find-Outers any of the things he had learnt. The postman came continually to the three homes, and cards soon stood everywhere. Parcels were hidden away, Mince-pies were made. Large turkeys hung in the larders.

“I do love Christmas,” said Bets a hundred times a day. “I wonder what I shall get on Christmas morning. I do hope I get a new doll. I’d like one that opens and shuts its eyes properly. I’ve only got one doll that does that, and her eyes always stick shut. Then I have to shake her hard, and I’m sure she thinks I’m cross with her.”

“Baby!” said Pip. “Fancy still wanting dolls! I bet you won’t get one.”

To Bets’ great disappointment there was no doll for her in her Christmas parcels. Everyone thought that as she was now nine, and liked to say she was getting big, she wouldn’t want a doll. So her mother had given her a work-basket and her father a difficult jigsaw which she knew Pip would like much better than she would!

She was rather sad - but Fatty put everything right by coming round on Christmas morning with a big box for Bets - and inside was the doll she had wanted! It opened and shut its eyes without any shaking at all, and had such a smiling face that Bets lost her heart to it at once. She flung herself on Fatty and hugged him like a small bear.

He was pleased. He liked Bets. Mrs. Hilton was surprised at the beautiful doll.

“That is very kind of you, Frederick,” she said. “You shouldn’t have spent so much money on Bets, though.”

“I shall have plenty for my birthday,” said Fatty politely, “and I’ve heaps for Christmas, Mrs. Hilton. I asked for money this Christmas instead of toys or books.”

“I should have thought you had plenty without asking for any more,” said Mrs. Hilton, who privately thought that Fatty always had far too much money to spend. “Why did you want so much money?”

“Well - to spend on something I didn’t think people would give me,” said Fatty, looking rather uncomfortable. “It’s a bit of a secret, really, Mrs. Hilton.”

“Oh,” said Bets’ mother. “Well, I hope it’s nothing that will get you into trouble. I don’t want Mr. Goon, the policeman, round here complaining about you children any more.”

“Oh no, Mrs. Hilton,” Fatty assured her. “Mr. Goon doesn’t come into this at all.”

As soon as her mother had gone Bets turned to Fatty with sparkling eyes. “What’s the secret? What are you going to buy?”

“Disguises!” said Fatty, dropping his voice to a whisper. “Wigs! Eyebrows! Teeth!”

“Oooh - teeth!” said Bets, in wonder. “But how can you wear false teeth without having your real teeth out, Fatty?”

“You wait and see,” said Fatty mysteriously.

“Do come after Christmas as soon as you can and teach us how to write invisibly and how to get out of locked rooms,” begged Bets. “I say - I wonder if old Clear-Orf knows those things?”

“Course not!” said Fatty scornfully. “And if Clear-Orf tried to disguise himself it wouldn’t be a bit of good. We’d always know his frog’s eyes and big fat nose.”

Bets giggled. She hugged her doll, and thought how clever and kind Fatty was. She said so.

“Oh, well,” said Fatty, swelling up a little, prepared to boast to his heart’s content, “I’m -”

But just then Pip came into the room and Fatty stopped. Pip didn’t take kindly to Fatty’s boasting. Fatty had a few words with Pip and then went.

“I’ll come along after Christmas and give you all some Find-Outers lessons,” he promised. “Give my love to Daisy and Larry if you see them today. I’ve got to go over to my grandmother’s for Christmas with my mother and father.”

Bets told Pip what Fatty had said about spending his money on disguises. “He said he would buy wigs - and eyebrows - and teeth!” said Bets. “Oh, Pip, do you think he will? What shop sells things like that? I’ve never seen any.”

“Oh, I suppose they are shops that actors go to,” said Pip. “They have to buy things like that. Well, we’ll see what Fatty gets. We ought to have some fun.”