Jo grinned. She was very happy. She suddenly remembered something and put her hand into the little rush basket she still carried. She took out an enormous key.

“Here you are,” she said to the sergeant. “Here’s the key to the tower room. I bet Red and the others are still locked up there, ready for you to catch! My, won’t they get a shock when you unlock the door and walk in!”

“Quite a lot of people are going to get shocks,” said the sergeant, putting away his very full note-book. “Miss Georgina, you’re lucky to get away unharmed, you and your dog. By the way, we got in touch with a friend of your father’s, when we tried to find out about those papers that were stolen. He says your father gave him all his important American papers before he went — so this fellow Red hasn’t anything of value at all. He went to all his trouble for nothing.”

“Do you know anything about Red?” asked Julian. “He seemed a bit mad to me.”

“If he’s the fellow we think he is, he’s not very sane,” said the sergeant. “We’ll be glad to have him under lock and key — and that man Markhoff too. He’s not as clever as Red, but he’s dangerous.”

“I hope he hasn’t escaped in that helicopter,” said Dick. “He meant to go tonight.”

“Well, we’ll be there in under an hour or so,” said the sergeant. “I’ll just use your telephone, if I may, and set things going.”

Things were certainly set going that night! Cars roared up to Red’s house, and the gate was broken in when no one came to open it. The helicopter was still in the yard — but alas! it was on its side, smashed beyond repair. The children were told afterwards that Markhoff and the other two men had tried to set off in it, but there was something wrong — and it had risen some way and then fallen back to the yard.

The old woman was trying to look after the three hurt men, who had crawled from their seats and gone to bathe their cuts and bruises. Markhoff had hurt his head, and showed no fight at all.

“And what about Red?” the sergeant asked Markhoff. “Is he still locked up?”

“Yes,” said Markhoff, savagely. “And a good thing, too. You’ll have to break that door down with a battering-ram to get him and the others out.”

“Oh no, we shan’t,” said the sergeant, and produced the key. Markhoff stared at it.

“That kid!” he said. “She gave me the key of the larder. Wait till I get her — she’ll be sorry.”

“It’ll be a long wait, Markhoff,” said the sergeant. “A long, long wait. We’ll have to take you off with us, I’m afraid.”

Red, Simmy and Jake were still locked up, and were mad with rage. But they saw that the game was up, and it wasn’t long before all of them were safely tucked away in police cars.