With, the help of the others, Fatty managed to get together some old clothes very like the old man on the bench had worn. Pip produced a very old gardening hat belonging to his father. Larry found an old coat hanging in the garage.

"It's been there for years, as far as I remember," he said. "Nobody ever wears it. You might as well have it. It's got mildew inside the pockets, so be careful how you put your hands in them!"

It was easy to get an old shirt and muffler. Fatty produced a torn shirt of his own, and found a muffler down in the garden shed, which he must have left there months before.

He dragged the shirt in the dirt, and it was soon as filthy as the old man's. He dirtied the muffler a little more too.

"What about the shoes?" he said. "We want frightfully old ones. That old man's were all cracked open at the toe."

The shoes were a real problem. Nobody’s father had shoes as old as that. The children wondered if they could buy a pair from some tramp, but when they went out to find a tramp, the only one they met had perfectly good shoes on.

Then Daisy had a brain-wave. "Let's look in all the ditches we pass!" she said. "There are always old boots and shoes in ditches, I don't know why. We might find some there."

Sure enough they did! Larry came across a dirty,-damp old pair, open at the toes and well worn at the heels. He tossed them to Fatty.

"Well, if you think you really do want to wear such horrible things, there you are! But you'll have to dry them or you'll get awfully damp feet, and have a streaming cold."

"He'll be able to sniffle properly then," said Bets. She too had been practising the old man's sniff, much to her mother's annoyance.

"Ill put them under the tank in the hot cupboard," said Fatty. "They'll soon dry there. They'll about fit me. I don't at all like wearing them, but, after all, if it's important to solve the Mystery, it's important to put up with little things like this!"

The trousers seemed quite impossible to get. Nobody's father wore the kind of coarse corduroy that the old man wore. Could they possibly buy a pair in the village shop and make them torn and dirty for Fatty to wear?

"Better not buy them in Peterswood, in case the news gets round," said Fatty. "I wouldn't want old Goon to know I'd bought workman's corduroys—he'd be sure to snoop round and find out why. He's got more brains lately, somehow."

"We'll walk across the fields to Sheepridge," said Daisy. "We might buy a pair there."

Half-way across the fields Pip gave a shout that made every one jump. He pointed to an old scarecrow standing forgotten in a field. It wore a hat without a brim, a ragged coat—and a pair of dreadful old corduroy trousers!

"Just what we want!" said Fatty joyfully, and ran to the scarecrow. "We'll give them back to him when we've finished with them. Golly, aren't they holey? I hope they'll hang together on me."

"I'd better give them a wash for you," said Daisy. "They really are awful. If you wear your pair of brown flannel shorts under them, Fatty, the holes won't show up so much. There are really too many to mend."

Joyfully the Find-Outers went back to Larry's. Daisy washed the trousers, but not much dirt came out of them because the rain had washed them many a time. Bets couldn't imagine how Fatty could bear to put on such horrid old-clothes.

"Duty calls!" said Fatty, with a grin. "Got to do all kinds of unpleasant things, Bets, when duty calls. And a really good detective doesn't stick at anything."

The next day they held a dress rehearsal and dressed Fatty up in the old clothes. He had already got a ragged, sandy-grey beard, which he had cut more or less to the shape of the old man's. He had shaggy grey eyebrows to put on too, and wisps of straggly grey hair to peep out from under his hat.

He made himself up carefully. He put in some wrinkles with his grease-paints, and then screwed up his mouth so that it looked as if he hadn't many teeth.

"Oh, Fatty—you're marvellous!" cried Bets. "I simply can't bear to look at you, you look so awful. Don't stare at me like that! You give me the creeps! You're an old, old man, not Fatty at all!"

"Wassat?" said Fatty, putting his hand behind his ear. He had very dirty hands indeed—and this time he had remembered to blacken his nails too. He really looked appalling.

"What's the time?" he asked, for he had taken off his wrist-watch, in case it showed. "Oh, twelve o'clock. Well, what about shuffling off for a snooze in the sun, on that bench? My double won't be there, because he said he never goes out till the afternoon. Come on. I'll see if I can play my part all right!”

"We'll all come," said Pip. "But well not sit near you. Well go and have lemonade in that little sweetshop opposite the bench. We can keep an eye on you then, and see what happens."

Fatty, after sending Larry down his garden path to the back gate, to see if the coast was clear, shuffled down, hoping that nobody in his house would spot him. He didn't want his mother to get curious about the odd old men and women that seemed to haunt her back-entrance.

Once out in the road, the other four children kept near to Fatty, but not near enough to make any one suspect they were with him. He shuffled along, dragging his feet, bent and stooping, his hat well down over his ears.

"He's just exactly like that old fellow we saw!" whispered Bets to Daisy. "I'd never know the difference, would you?"

Fatty did a loud sniff and the others grinned. He came to the sunny bench and cautiously sat himself down, giving a little sigh as he did so. "Aaaah!"

He was certainly a marvellous actor. He sat there in the sun, bending over his stick, the very picture of a poor old man having a rest. The others made their way to the little lemonade shop, and sat down at the table in the window to watch him.

Just as they were finishing their lemonade a man came by on a bicycle, whistling. He was a perfectly ordinary man, in a perfectly ordinary suit and cap, with a very ordinary face. But, when he caught sight of the old man, he braked very suddenly indeed, and looked at him in some astonishment.

He got off his bicycle and wheeled it over to the bench. He leaned it against the seat and sat down by Fatty. The children, watching from the shop opposite, were surprised and rather alarmed. Had this man seen something queer about Fatty's disguise? Had he guessed it was somebody pretending? Would he give Fatty away?

Fatty, too, felt a little alarmed. He had been enjoying himself thoroughly, getting right "under the skin" of the old man, as he put it to himself. He had seen the look of surprise on the man's face. Now here he was sitting beside him. Why?

"What you out here for, in the morning?" said the man suddenly, in a very low voice. "Thought you never came till the afternoon. Anything up? Expecting any one?"

Fatty was taken aback to hear this low and confidential whisper. Obviously the man thought him to be the old fellow, and was amazed to see him out in the morning. But what did all the questions mean?

Just in time, Fatty remembered that the old man was deaf. He put his hand to his ear and put his ear towards the man, so that he should not look directly into his face. He was afraid that he might be recognized as a fraud if the man looked into his eyes.

"Wassat?" said Fatty, in a croaking old voice. "Wassat?"

The man gave an impatient exclamation. "Of course—he's deaf!" He gave a quick look round as if to see if any one was near. Then somebody else cycled slowly by and the man sidled a little way away from Fatty, and took out a cigarette to light.

The cyclist was Goon, perspiring freely in the hot sun. He saw the two men at once, and got off his bicycle. He pretended to adjust the chain. The four children in the shop watched him with interest, hoping that he wouldn't go and say anything to Fatty.

Buster saw Goon, and with a delighted yelp he tore out of the sweet-shop, and danced round the policeman's feet. Larry rushed after him, afraid that Buster would go and lick Fatty's face, and give the show away to Goon. But Buster was fully engaged with the angry policeman, and was having a perfectly lovely time, dodging kicks, and getting in little snaps and snarls whenever he could.

Fatty got up hurriedly and shuffled away round the nearest corner without being noticed by Mr. Goon, who was rapidly losing his temper. All the others, seeing Fatty wanted to get away before Goon noticed he was gone, began to join in the fun, pretending to call Buster off, but only succeeding in exciting the little Scottie more than ever!

When at last Buster was safely in Larry's arms, and Goon could look round at the bench, it was empty! Both the men had gone. Mr. Goon looked extremely angry.

"That there dog!" he said, dusting his trousers down violently. "I'll report him, I will. Interfering with me doing my duty, that's what he did. And now where are them two fellows gone? I wanted to put a few questions to them!"

"They've disappeared," said Daisy. Mr. Goon did one of his snorts.

"No need to tell me that. I've got eyes in my head, haven't I? I may have lost a Most Important Clue! See? Where's that fat boy that's always with you? I bet he's at the bottom of this!"

"He isn't here," said Larry truthfully. "You'll probably find him at home if you badly want to see him, Mr. Goon."

"I wouldn't care if I never set eyes on him again, the cheeky toad!" said Mr. Goon, mounting his bicycle rather ponderishly and wobbling a little. "No, nor any of you neither. As for mat dog!"

He was about to ride off, when he stopped, wobbled again, and spoke to Larry.

"Where were you just now?"

"In the sweet-shop, having lemonade," said Larry. "Ho," said Mr. Goon. "And did you see that old fellow sitting on that bench?"

"Yes, we did," said Larry. "He seemed half-asleep and quite harmless."

"And did you see that other fellow talking to him?" demanded Mr. Goon.

"Well—he may have spoken to him. I don't know," said Larry, wondering why the policeman was asking all these questions.

"You'd better come alonga me," said Mr. Goon, at last. "I'm going to call on that old fellow, see, and I want you to back me up when I tell him I want to know about the other fellow."

The children felt distinctly alarmed. What! Mr. Goon was going to visit the real old man—who would probably be in bed—and ask him questions about the other man, whom he hadn't been there to see! Whatever would the poor old fellow say? He wouldn't in the least know what Mr. Goon was talking about!