The next time the Five Find-Outers met they roared with laughter at Fatty’s story. He acted it well, and the children could imagine exactly how poor Mr. Goon had looked.

“And now he really does think we’re on to some mystery he doesn’t know about,” said Fatty. “Poor old Clear-Orf - we’ve got him really puzzled, haven’t we! Mother tells me he has been making inquiries all over the place to find out where the ‘Frenchy fellow’ is staying, but nobody can tell him anything, of course.”

“I do, do wish there was a mystery to solve now,” sighed Bets, tickling Buster. “We’ve got all sorts of good detective tricks - invisible writing - how to get out of a locked room - disguises - but there’s nothing to solve.”

“We’ll just have to go on playing a few tricks on Clear-Orf,” said Fatty. “That’ll keep our wits sharp, anyway. Pip, would you like to wear a disguise today, and go and do a bit of parading where Clear-Orf is?”

“Yes,” said Pip, who had now tried on all the eyebrows, teeth, and wigs and painted his face a curious collection of colours. “I’d love to. Let me wear the other wig - the straight-haired one, Fatty - and the teeth - and those big black eyebrows. They’re lovely. And I might give myself a red face like Clear-Orfs too.”

This sounded exciting. Every one helped Pip to put on his disguise.

“I don’t see why you haven’t bought any moustaches too,” said Pip, thinking that he would look grand in a black moustache.

“Well, we haven’t got voices to match moustaches,” said Fatty. “You want a man’s voice for that. I did think of bringing back a moustache or two, but it wouldn’t be a proper disguise for us. We can only disguise ourselves as some kind of children. There - you look positively frightful!”

Pip did. He had a fiery red face, black, fierce eyebrows, the awful jutting-out teeth, and the straight-haired wig. He borrowed a red scarf from Daisy, put on his mackintosh inside out, and then felt himself sufficiently disguised.

Goon always goes down the village and round the corner at half-past eleven,” said Larry. “There won’t be any one much about today, it’s such an awful day, and there’s a fog coming on. Wait round the corner for him, and then ask him the time or something.”

“Please, sir, what’s the time?” said Pip, in an astonishingly deep, hoarse voice. Every one laughed.

“That’s fine,” said Larry. “Well, off you go, and come back quickly and tell us what happened.”

Pip set off. Down in the village it was foggy. He could hardly see more than a yard in front of him. He waited about at the corner, listening for Clear-Orf’s heavy feet. Some one came unexpectedly round the corner, walking quietly and lightly.

Pip jumped - but the other person jumped much more! The sight of Pip’s fiery face, fierce eyebrows, and awful teeth made old Miss Frost scream.

“Oh! Help! Who is it?” she squealed, and turning back, she raced down the village street. She bumped into old Clear-Orf.

“There’s a horrible person round the corner,” she panted. “Awful red face and great eyebrows - and the wickedest teeth I ever saw - sort of hanging out of his mouth!”

The mention of sticking-out teeth reminded Mr. Goon of the French boy, and he wondered if it was he who was hanging about round corners. So, trying to walk as lightly as he could, he tiptoed to the corner and went round it very suddenly.

Pip was there! Mr. Goon was on him almost before he could move. The policeman stared in amazement at the boy’s fiery face, the absurd eyebrows, and the familiar jutting-out teeth.

“’Ere, what’s all this?” he began, and shot out a powerful arm to get hold of Pip. Pip felt his grip on his mackintosh, and had to wriggle right out of it before he could escape. Mr. Goon was left standing with a mackintosh in his hands - but he didn’t stand for long. He went after Pip at top speed.

Pip was frightened. He hadn’t really thought Mr. Goon would catch hold of him so quickly - and now he had got his mackintosh. Blow! Well, he mustn’t be caught, or there would be very awkward questions to answer. For a minute he was sorry he had gone out in such an extraordinary disguise. Then as he gained a little on the panting policeman, he began to enjoy the adventure.

They tore up the road. They raced up the hill and over it. Pip made for open country, thinking that he might be able to get behind a hedge and let Mr. Goon go lumbering by in the mist.

He came to a gateway, and remembered that it led up the drive to an old empty house. No one had lived there for ages and ages. It belonged to somebody who seemed to have forgotten all about it!

He tore into the drive, hoping that Mr. Goon would go on without seeing him. But the policeman was not to be put off so easily. He tore up the drive too.

Pip fled round the old house, and came into a tangled, untidy garden, with many trees standing about. He spotted one that seemed easy to climb, and in a trice had shinned up it, just before Mr. Goon came round the corner, puffing like a goods train.

Pip sat high up in the tree, as silent as could be. There were no leaves on it and if Mr. Goon looked up he was lost! He watched the policeman go all over the garden, and took the chance of climbing up still farther, so that more branches hid him from Mr. Goon. He was almost at the top of the tree now, level with the highest storey of the house. He watched Mr. Goon, hardly daring to breathe.

“Jolly good thing this is an empty house,” thought Pip, “else the people would all be coming out to see what the matter is - and I’d be spotted.”

He crouched against the trunk of the tree, level with a window. He looked at it, and saw to his surprise that it was barred.

“Must have been a nursery window at one time, I suppose,” he thought. “Jolly strong bars though.”

Then he glanced in at the window - and he almost fell out of the tree with shock!

The room inside was not empty. It was fully furnished!

Pip couldn’t understand it. If the house was empty, how could a room on the top storey be furnished? People didn’t move away and forget all about one room!

“Golly! - I wonder if this is the old empty house after all,” thought Pip. “Perhaps in the fog I’ve run in at a different gate. Maybe the house is lived in, and all the rooms are furnished. I wish old Clear-Orf would go, then I could have a look round.”

Clear-Orf was hunting everywhere. The garden was well hedged in, and no one could squeeze out of the sides. Then where had that queer fellow gone? It was a real puzzle to the policeman. It never once occurred to him to look up into any of the trees.

At last he gave it up. His prey had escaped him - but next time - ah, next time he saw any one with those awful teeth, he’d get them! There was something funny about two people having the same sticking-out teeth.

“I never did see teeth that stuck out so,” thought the defeated Mr. Goon, as he made his way round the side of the house and walked to the front gate. “That Frenchy fellow had them, and so had this one I’m after now. Wish I could have caught him. I’d have asked him a few straight questions, I would!”

Pip was very thankful to see him go. He waited till the policeman had disappeared round the house, and then he cautiously slid along a branch to the window, in order to get a better look inside.

There was no doubt about it at all. The room had plenty of furniture in it - a couch that was big enough for a bed, an arm-chair, two smaller chairs, a table, a book case with books in, a carpet on the floor. It was all most extraordinary.

“There’s an electric fire there too,” said Pip to himself. “But there’s no one there - and judging by the dust everywhere, there hasn’t been any one for some time. I wonder who the house belongs to.”

He looked at the bars on the window. No one could possibly get in or out of the window, that was certain. The bars were as close together as most nursery-window bars are - not even a child could slip between them.

Pip climbed cautiously down the tree, keeping a sharp look-out in case Mr. Goon was lurking somewhere. But that puzzled man had gone back to the village, comforting himself with the thought that though he had lost the boy with the teeth and eyebrows, he had at least got his mackintosh! Wait till he saw if there was a name inside!

Pip felt cold without his mackintosh. He thought ruefully of how he could explain its loss to his mother. Perhaps she wouldn’t notice it was gone. On the other hand, mothers invariably noticed anything like that almost immediately.

The fog was now getting very thick. Pip would have liked to stay and snoop round a bit, but he was afraid of getting lost if the fog grew much thicker. So he contented himself with making quite sure that the house was indeed the empty one he knew.

It was. There was no doubt about it - and the rooms on the ground floor were perfectly empty. On the gate was the name Pip had seen before - Milton House.

“It’s a mystery!” said Pip, as he plodded back in the fog. “A real mystery.” Then he stopped suddenly and hugged himself. “This might be our third mystery! We shall have to solve it somehow. There’s something very queer going on in that old empty house!”