Fatty went straight to Pip's. He felt sure he would find the rest of the Find-Outers there, waiting for him. They were outside the summer-house, making Larry tell them over and over again all that had happened.

"Here's Fatty!" cried Bets. "What did the Inspector say, Fatty? Wasn't he angry with Goon for leaving you in that cupboard?"

"He wasn't very pleased with him—at least he didn't sound very pleased," said Fatty. "He didn't sound very pleased with me either! Seemed to think I oughtn't to have got so mixed up in this Mystery. But how could I keep out of it?"

"I expect he (thought it was dangerous," said Bets, "and so it was, last night. Oh, Fatty, I knew you were in danger. I really, really did."

"Good old Bets!" said Fatty, giving her a hug. "I'm jolly glad you had one of your funny feelings about me—if you hadn't sent Pip to Larry, and Larry hadn't come along to the Waxworks Hall, goodness knows how long I'd have been shut up in that cupboard. By the way—the Mystery is still not quite ended!”

Every one sat up at once. "What do you mean?" said Daisy.

Fatty explained about the missing pearls and Number Three. "The Inspector thinks that Number Five, who escaped with the pearls last night, had time to put them in some safe place, before he was caught this morning. He will probably try and get a message to Number Three—the gang member who wasn't there last night and so is still at large—and till Number Three gets that message about the pearls and finds them, any one might find them! And it's up to us to do it!"

"I see," said Larry slowly. "But how in the world can any one find them if they don't even know where to look? It's impossible."

"Nothing's impossible to a really good detective," said Fatty. "I agree that it's a frightfully difficult mystery to solve—but I think if only we can get hold of Number Three somehow, and shadow him, he might lead us to the necklace!"

"What do you mean—shadow him?" asked Bets.

"Follow him, silly—always keep him in sight," said Pip. "Spot where he goes, or where he hangs about. He's sure to hang about the place where the pearls are, waiting for a chance to get them."

"That's right," said Fatty. "The thing is—who is Number Three and how can we get hold of him?"

There was a silence. Nobody knew the answer.

"What do we know about Number Three?" said Fatty, considering. "We know he rides a bike that has a hooter on it. We know he has odd eyes, one blue and one brown. And we know he rows a boat. I rather think, as we've seen him in Peterswood twice that he must live here."

There was another silence. None of the things they knew about the odd-eyed man seemed to be of any help in finding him. Then Pip suddenly gave an exclamation.

"I think I know what to do!"

"What? " said every one eagerly.

"Well, we're sure that Number Five hid the pearls somewhere, and we're pretty certain he'll get a message to Number Three, somehow—has probably sent one already, in case he himself got caught by the police and put into prison. Now who would he send that message to, to deliver to Number Three? "

"The old man, Johnny, of course!" said Fatty. "He's the one they always use, apparently, when they want to send messages to one another. So—if we watch old Johnny again—sooner of later we'll see Number Three go quietly up to him...."

"Sit down beside him—and receive the message!" said Larry. "And if we shadow him, after that, we shall spot where he goes. Maybe hell lead us straight to the necklace!"

Every one felt much more cheerful and hopeful. "That's a brain-wave of yours, Pip," said Fatty. "I'm surprised I didn't think of it myself. Very good."

All the Find-Outers loved a word of praise from their leader. Pip went quite red with pleasure.

"I suppose that means we must go and sit in that smelly little lemonade shop again," said Daisy. Fatty considered.

"Only one of us had better shadow Number Three closely," he said. "If he sees five of us tailing him he's bound to get a bit suspicious. I'll do the shadowing—if you don't mind, Pip, though it was your idea—and you can all follow me at a safe distance."

"I don't mind a bit," said Pip generously. "I'm sure you'll be much better at shadowing than I shall. Where will you wait? And shall we have bikes or not?"

"Better have bikes," said Larry. "He was on a bike last time he went up to the old man. If he's walking we can always leave our bicycles somewhere, and walk after him."

"Yes, that's a sound idea," said Fatty. "What's the time? Almost dinner-time. The old fellow doesn't come out till the afternoon, so well meet just before two, at the bottom of my lane, with bikes."

"But, Fatty, do you think the old man will come out and sit on your seat, after your warning, and after what he will have read in the papers today?" asked Larry. "Wont he be afraid?"

"Yes, probably he will," said Fatty. "But if he has a message to deliver, I think he'll risk it. I bet the gang pay him well for this go-between business."

Now that there was something to do; Outers felt very cheerful. They went to their dinners pleased that there was still a Mystery to solve. If only they could find those pearls before Goon did!

Mr. Goon, of course, was exercising his mind too, about the missing pearls. He too knew that if only he could spot Number Three, he might be led to the pearls. But he had not got as far as reckoning out that it would be a good idea to watch old Johnny again, to see if Number Three came to receive a message!

That afternoon four of the Find-Outers sat in the little sweet-shop, on the opposite side of the road to the bench where the old man so often sat. Fatty was not with them. He was leaning against a tree not far off, apparently deep in a paper, his bicycle beside him. He was watching for the old man to come. How he hoped he would!

The bicycles belonging to the others were piled against the side of the sweet-shop. The four children in the shop were eating ices, and watching the bench opposite as keenly as Fatty was.

Some one came shuffling round the corner. Hurrah! It was the old man, complete with sniffle and pipe and cough. He sat himself down gingerly on the bench with a little groan, just exactly as Fatty used to do.

Then he bent himself over his stick-handle and seemed to go to sleep. The children waited, whilst their ices melted in the saucers. Had Johnny got a message to deliver from Number Five to Number Three?

A noise made them jump violently. It was the sound of a hooter! Fatty jumped too. He lifted his head cautiously from his paper, and saw a man riding down the High Street on a bicycle.. It had a hooter instead of a bell.

The man rode to the bench, hooted, and got off his bicycle. He stood his machine against the kerb and went to sit down on the bench close to the old man.

The old fellow did not even look up. How would he know if it was Number Three or not then? He was deaf and would not hear a whisper. Fatty puzzled his brains to think.

"Of course!" he thought suddenly. "That loud hooter always tells the old man when Number Three is coming to sit on the bench beside him. Of course! Gosh, that's clever."

The old man took absolutely no notice of the other man. Fatty watched very carefully, but he could not see any movement of the old man's mouth, nor could he see the giving of any paper-message.

For a few moments the two men sat together, and then old Johnny sat up a little straighter, and began to draw patterns in the dust with the end of his stick. Fatty watched more carefully to see if the old man was talking, under cover of his movements. But he could not make out that he was—unless he could talk without moving his lips, as a ventriloquist can!

After a minute or two the other man got up and went to his bicycle. He got on it, hooted, and rode slowly over to the sweet-shop. The four children in there stiffened with excitement. What was he coming over there for?

Bets gave a gasp as he came in, and Pip kicked her under the table, afraid she might give them away. Bets took one look at the man and then began to finish her ice, making rather a noise with her spoon.

"Box of matches, please," said the man, and put a penny down on the counter. Nobody liked to look at him in case he became suspicious of them.

He went out, lighting a cigarette. "He's got odd eyes!" said Bets. "He's the one! Hooter on his bike—and odd eyes! Oooh—it's getting exciting."

Fatty, waiting by the tree outside, saw the man go in and out of the shop. The boy folded up his paper quickly, and mounted his bike as the man went swiftly by him. He followed him at a discreet distance, wondering if he had had any message, and if he was going to lead him to the pearls!

"Come on," said Larry, going out of the shop quickly. "We've got to follow too."

The man rode down to the Fair. He wandered round a bit and then went to the Hall of Waxworks. But he only just put his head inside, and came out.

Fatty popped his head inside too, but except that it was full of people looking at the waxworks, there was nothing different to see. Napoleon was dressed and back in his place, and the red-haired boy was relating an extraordinary tale of how, in the night, Napoleon had apparently got out of his place, undressed and put himself to bed in a cupboard.

"Story-teller!" said some listening children. "What a fib!"

"And what's more," said the red-headed boy, thoroughly enjoying himself, "that wax policeman over there—do you see him? Well, he got up in the night and went and stood himself behind that curtain. Such goings-on!"

Fatty longed to hear more of this, but the man he was following had gone, and Fatty had to go too, or lose him.

The man had put his bicycle beside the hedge and pad-locked the back wheel, so Fatty knew he meant to stay around for a while.

The other Find-Outers came up, and Fatty winked at them. "Looks as if we're going to spend an hour or two in the Fair!" he said.

The man wandered about most aimlessly. He didn't even have a ride on the roundabout, or try for a Hoopla gift, or go in a Bumping Car—he just trailed about. Every now and then he passed the Waxworks Hall, and looked inside. But he didn't go in at all. Fatty wondered if he was waiting for somebody to meet him there.

"I don't believe he knows where the pearls are!" thought Fatty. "Or surely he'd go straight to them! My word what a crowd there is at the Fair today!"

The man evidently thought the same. He asked a question about it of the man at the Hoopla stall. "Quite a crowd today I What's up?"

"Oh, it's a trip from Sheepsale, a kind of outing," said the man. "They're going at four o'clock, then the place will empty a bit. Good trade for us, though!"

The man nodded. Then he made his way through the crowd to his bicycle, and unpadlocked it. Fatty followed him. It was clear that the man couldn't do whatever he wanted to do, because the place was too crowded. Probably he would be coming back. It was up to Fatty to follow him. He would leave the others down in the Fair, because he was sure that he and the man would be back there sooner or later, when the trippers had gone.

He had time to give a quick message to Larry. Then off he went over the level-crossing on his bicycle, following the man as closely as he dared. Round the corner they went, the man hooting with his little hooter—parp-parp.

And round the corner on his bicycle came Goon! The two almost collided. Goon, who had heard the hooter, glued his eyes on the man at once. Was he Number Three? He must be! He seemed to be the only man within miles who had a hooter on his bicycle, instead of a bell, for some peculiar reason that Goon couldn't guess.

Goon made up his mind to follow Number Three at once, and keep him in sight. Visions of pearl necklaces floated in front of his eyes. Number Three knew where those pearls were, Goon was sure of it. Off he went after Number Three.

And behind him went Fatty, annoyed and angry. Was Goon going to get in first again! Goon heard some one behind him and turned. He scowled.

That fat boy again! Was he after Number Three too. "Gah!" said Goon to himself. "The interfering Toad!"