"He said he'd come back and let me out of that cupboard when the fun was over," said Fatty, beginning to grin. "Hell be surprised to find I'm gone, won't he?"

"He will," said Larry. "He won't know what's happened. Let's pretend to him that we don't know where you are, shall we? We'll go and ask him about you tomorrow—hell have twenty fits if he thinks you've vanished. He won't know what to think!"

"And he'll feel most uncomfortable because hell know he jolly well ought to have let me out," said Fatty. "Well, I'm going to bed, Larry. You'd better go and get some sleep too. Oh, I do feel so disappointed—after all our work and disguises and plans—for Goon to solve the Mystery and get all the credit!"

The boys parted and Larry ran swiftly home. He wondered what Goon was doing. He thought about the Castleton Mansion and wondered if the thieves were at work—if the house was being quietly surrounded—if Goon was doing some arresting. Well, maybe it would all be in the papers tomorrow.

Goon had certainly done some good work that night. He had surrounded the mansion with men whilst the thieves were actually inside. He had arrested all four of them—although one, alas, had got away in the struggle—and Goon was feeling very pleased with himself indeed. Not a doubt of that.

It wasn't until past midnight that Mr. Goon suddenly remembered that he had left Faitty locked up in the cupboard in the Waxworks Hall.

"Drat mat boy!" he thought. "I could go to bed now, and sleep easy, if it wasn't for getting him out of that cupboard. He's had a nice long time there to think over all his misdeeds, he has. Well, I'd better get along and let him out—and give him a few good words of advice too. He's missed all the fun this time—and I've solved this Mystery, not him! Ha!"

Mr. Goon cycled down to the Waxworks Hall and, leaving his bicycle outside, went into the Hall. He switched on his torch and walked to the cupboard. He rapped smartly on it.

"Hey, you!" he said. "Ready to be let out yet? We've done everything, and now that the fun's over, you can come along out!"

There was no answer. Mr. Goon rapped loudly again, thinking that Fatty had gone to sleep. But still there was no answer. A little cold feeling crept round Mr. Goon's heart. Surely that boy was all right?

Hurriedly Mr. Goon turned the key in the lock and opened the door. He shone his light into the cupboard. Napoleon looked back at him, standing there in his under-garment—but no Fatty! Mr. Goon's hands began to tremble. Where was that boy? He couldn't get out of a locked cupboard! Or could he? Mr. Goon remembered how Fatty had apparently passed mysteriously through a locked door in the last Mystery.

Mr. Goon poked Napoleon in the ribs to make sure he was wax, and not Fatty. Napoleon did not flinch. He looked straight at Mr. Goon. Yes, he was wax all right. Mr. Goon shut the door, puzzled and upset. Now where was that boy? Had somebody carried him off? He had seen him bound and gagged, so he couldn't have escaped by himself. Well, then, what had happened?

Mr. Goon went home slowly, pedalling with heavy feet. He ought to have let that boy free before he had gone after the gang. Suppose he didn't turn up in the morning? What explanation could he give to the Inspector? He was seeing him at ten o'clock.

Mr. Goon gave a heavy sigh. He had been looking forward to that interview—now he wasn't so sure. That fat boy was very friendly with the Inspector. If it came out that anything had happened to him, Inspector Jenks might ask some very very awkward questions. Drat the boy!

Fatty slept soundly that night, tired out with his adventures. Mr. Goon slept too, but not so soundly. He dreamt about his great success in arresting the gang—but every time he was about to receive words of praise from the Inspector, Fatty came into the dream, tied up, begging for help. It was most disturbing, because he woke Mr. Goon up each time, and then he found it hard to go to sleep again.

At nine o'clock the Five Find-Outers were all together in Pip's garden, going over and over the happenings of the night before. All of them were most indignant with Goon for leaving Fatty in the cupboard.

"We're going to make him think Fatty's been spirited away," said Larry, with a grin. "We'll wait about the village for him, and each time he passes any of us we'll ask him if he's heard anything of Fatty."

So, at half-past nine the children, with the exception of Fatty, of course, hung about near Goon's house, waiting for him to come out. Larry was at the corner, Pip was near the house, and Daisy and Bets were not far off.

Larry gave a whistle when he saw Goon coming out, wheeling his bicycle, ready to ride over to see the Inspector. He looked very smart indeed, for he had brushed his uniform, cleaned his belt and helmet and shoes, and polished his buttons till they shone. He was the very picture, he hoped, of a Smart Policeman Awaiting Promotion.

"I say, Mr. Goon!" called Pip, as the policeman prepared to mount his bicycle. "Do you know where our friend, Frederick, is?"

"Why should I?" scowled Mr. Goon, but his heart sank. So that boy had vanished!

"Well, we just wondered," said Pip. "I suppose you haven't seen him at all? "

Mr. Goon couldn't say that. He mounted his bicycle and rode off, his face red. He hoped that boy Fatty wasn't going to cause a lot of trouble, just as he, Goon, had got things going so very nicely.

He passed Daisy and Bets. Daisy called out. "Oh, Mr. Goon! Have you seen Fatty? Do tell us if you have!"

"I don't know where he is," said Mr. Goon desperately, and cycled on. But at the corner, there was Larry!

"Mr. Goon! Mr. Goon! Have you seen Fatty? Do you know where he is? Do you think he's disappeared? Mr. Goon, do tell us where he is. Have you locked him up?"

"Course not!" spluttered Mr. Goon. "He'll turn up. He'll turn up like a bad penny, you may be sure!"

He rode on, feeling most uncomfortable. Where could the boy be? Had that thief who escaped gone back to the Hall, and taken Fatty? No, that couldn't be, surely. But WHERE WAS that boy?

The Inspector was waiting for Mr. Goon in his office. On his desk were various reports of the happenings of the night before, sent in, not only by Mr. Goon, but by two other policemen who had helped in the arrests, and by plain-clothes detectives who had also been on the case.

He also had reports on what the three prisoners had said when questioned. Some smart work had been done, there was no doubt about that—but something was worrying the Inspector.

Mr. Goon saw it as soon as he got into the office. He had hoped and expected to find his superior officer full of smiles and praise. But no—the Inspector looked rather solemn, and a bit worried. Why?

"Well, Goon," said the Inspector, "some good work appears to have been done on this case. But it's a pity about the pearls, isn't it? "

Mr. Goon gaped. "The pearls, sir? What about them? We've got them, sir—took them off one of the gang."

"Ah, but you see—they are not the stolen pearls," said the Inspector gently. "No, Goon—they are just a cheap necklace the man was going to give his girl! The real pearls have vanished!"