Soon all the Find-Outers, and Buster, were in Pip's summer-house. Fatty changed as quickly as he could.

"I shan't use this disguise more than I can help," he said, pushing all the petticoats and skirts into the sack he kept them in. "It's too hot. I shall get as thin as a rake if I keep getting so melting-hot!"

"Oh, don't do that!" said Bets, in alarm. "You wouldn't be Fatty any more, if you were thin. And I do like you just exactly as you are!"

Plans were laid for the next few days. "These may be very important days," said Fatty. "We may be able to learn a lot—right under Goon's nose, too, if he's going to do this watch-dog act of his!"

"What exactly are we going to do?" said Daisy, thrilled. "You're going to disguise yourself as that old man, we know, and take his place, hoping for a message from one of the gang. But what are we to do? We must have something interesting so that we can do our share as Find-Outers."

"Woof," said Buster.

"He wants a job too," said Bets, with a laugh. "Poor Buster! He can't understand why you have to dress up as somebody different, Fatty. You don't look or sound the same to him—you only smell the same. And when you go out as the Balloon-woman or the old man, we have to lock Buster up and leave him behind, and he hates that."

"Poor old Buster-Dog," said Fatty, and at once Buster rolled himself over on his back to be tickled. His tongue came out, and his tail wagged so violently that it wagged his whole body and made it shake from end to end.

"Now," said Fatty, taking out his note-book and opening it. "Let's just have a look at what we know. Then we'll make our plans—and you shall each have something to do."

"Good," said Larry. "I know you've got to do all the important work, Fatty, because you really are a born detective—but we do want something as well."

"We don't know very much yet," said Fatty, looking at his notes. "We know that Goon is watching the old man because he suspects what we do—that he receives messages to pass on—and we feel certain that for some reason or other the headquarters are here in Peters-wood. We have also seen one of the members of the gang—the fellow with a hooter on his bike—but that's about all we do know."

"It's not very much," said Larry. "Not a scrap more than we knew the other day."

"We also know that the old fellow is likely to keep away from that seat for a while," said Fatty. "Goon doesn't know that. We're ahead of him there. We know that the old man who will be sitting on the bench this afternoon, and tomorrow and probably the next day too, will be me—and not that old fellow."

"Yes, that's one up to us," said Pip.

"Now," said Fatty, shutting his note-book and looking round, "tomorrow afternoon—in fact, each afternoon that I sit out on that bench, one or more of you must be in that sweet-shop, watching carefully to see if any one gives me a message—and it's your job to notice every single detail about him very carefully indeed. See? That's most important."

"Right," said Larry.

"And the other thing for you Find-Outers to do is to try and discover which cyclists have hooters on their bikes, instead of bells," said Fatty. "It would be a help if we could discover who that man was that came and spoke to me on the bench the other morning. We could watch him, and find out who his friends were, for instance."

"I don't see how we can possibly find out who has a hooter on his bicycle," said Pip. "We can't go and look into every one's bicycle sheds!"

"You could go to the shop that sells hooters and get into talk with the shopkeeper, and ask him if he sells many hooters, and maybe even get him to tell you the names of the buyers," said Fatty.

"Oh yes," said Pip. "I hadn't thought of that."

"I thought of it the other day when I went to buy that hooter," said Fatty. "But I hadn't time to talk to the man then—well, actually it's a boy in the shop I went to. I should think he'd love to have a good old jaw with you."

"I'd like to go and talk to him," said Bets. "With Daisy."

"You and Daisy and Pip can go, if you like," said Larry. "And I’ll watch the seat from the sweet-shop. Then, when you come back with all the information you can get you can take your turn at sitting in the shop and having lemonade, and I'll go and try and find out something else."

"Buster can go with the ones who are going to the hooter-shop," said Fatty. "But he mustn't go to the sweet-shop. He would smell me all across the road, and come bounding out, barking. Goon would soon think there was something funny about Buster making up to a dirty old man!"

The next afternoon Larry went out to the sweet-shop opposite the bench, and ordered a lemonade. Mr. Goon was there again, reading his newspaper. He was once more in plain clothes, and he scowled at Larry when he came in.

"Why, Mr. Goon! Here again!" said Larry, pretending to be most surprised. "You are having a nice holiday! Do you spend all your time in here?"

Mr. Goon took absolutely no notice. He felt very angry. Here was he, forced to spend his afternoons in a hot, smelly, little shop, watching a bench out there in the sun—and he couldn't even have peace! Those children had got to come and poke fun at him. Mr. Goon eyed Larry's back grimly, and thought of all the things he would like to do to him and the other Find-Outers.

Then Mr. Goon straightened up a little, for the old man was coming shuffling along to his bench. Larry watched him. He knew it was Fatty, of course, but Mr. Goon didn't. Larry marvelled at the way Fatty lowered himself slowly down on to the bench. That was just exactly the way bent old people did sit down! Fatty never made a mistake in his acting.

Fatty took out a pipe and began slowly to fill it. Then he coughed. It was a horrible, hollow cough, and bent him double. Larry grinned. The cough was new. He supposed Fatty must have heard the old man, and had practised the cough till it was quite perfect.

The old man put his pipe away without smoking it. Evidently he was afraid of its making him cough too much I Larry turned to Mr. Goon.

"There's that old man you made us go and see the other day, Mr. Goon. Funny about him, wasn't it? Did you ever find out what you wanted to know?"

Mr. Goon again took no notice, but rustled the paper noisily. Larry winked at the shop-woman. "Must have got a cold," he said sympathetically. "Gone quite deaf!"

"Now, you look 'ere!" said Mr. Goon, going red and rising quite suddenly, "if you don't..."

But just then two men came along, stopped by the bench and sat down. At once Mr. Goon subsided, and began to watch the men with much concentration. So did Larry. Were they going to pass a message to Fatty?

The men had papers. They opened them and began to discuss something. One of them lighted a pipe. They stayed there for quite a time, but neither Goon nor Larry could spot any message being given or received. The old fellow at the end of the bench still leaned over his stick, his head nodding occasionally.

Then he sat upright, gave a loud sniff and wiped the back of his hand across his nose. Larry was amused to see the two men give him a disgusted look. They folded their newspapers, got up, and, still talking, walked off down the street.

Mr. Goon leaned back and wrote down a few notes. Larry wondered if he thought they were the members of the gang. He was certain they weren't. For one thing he was sure that one of them was a friend of his father's.

Larry began to be bored. He had finished his lemonade. He really didn't want another, and he felt that he couldn't possibly eat an ice at that moment. The shop-woman came up to him.

"Anything else, sir?" she asked. Larry said no thank you.