George got up as if she was in a dream. She went across to the door. She and Jo slipped out, and stood at the top of the spiral staircase.

“Have to go down here, I suppose,” said Jo. She cocked her head and listened. Then she went down a few steps and turned the first spiral bend.

But before she had gone down more than a dozen steps she stopped in fright. Somebody was coming up!

In panic Jo ran up again and pushed George roughly into the room she had climbed into first of all.

“Someone’s coming,” she panted. “Now we’re finished.”

“It’s that red-haired man, I expect,” said George. “He comes up three or four times a day and tries to make me tell him about my father’s work. But I don’t know a thing. What are we to do?”

The slow steps came up and up, sounding hollowly on the stone stairs. They could hear a panting breath now, too.

An idea came to Jo. She put her mouth close to George’s ear. “Listen! We look awfully alike. I’ll let myself be caught and locked up in that room — and you take the chance to slip down and go to Dick and Julian. Red will never know I’m not you — we’ve even got the same clothes on now, because Joan gave me old ones of yours.”

“No,” said George, astounded. “You’ll be caught. I don’t want you to do that.”

“You’ve got to,” whispered Jo, fiercely. “Don’t be daft. I can open the window and climb down the ivy, easy as winking, when Red’s gone. It’s your only chance. They’re going to take you off in that helicopter tonight.”

The footsteps were now at the top. Jo pushed George well behind a curtain and whispered fiercely again: “Anyway, I’m not really doing this for you. I’m doing it for Dick. You keep there and I’ll do the rest.”

There was a loud exclamation when the man outside discovered the door of George’s room open. He went in quickly and found nobody there. Out he came and yelled down the stairs.

“Markhoff! The door’s open and the girl’s gone! Who opened the door?”

Markhoff came up two steps at a time, looking bewildered. “No one! Who could? Anyway, the girl can’t be far off! I’ve been in the room below all the time since I locked her in last time. I’d have seen her if she’s gone.”

“Who unlocked the door?” screamed Red, quite beside himself with anger. “We’ve got to have that girl to bargain with.”

“Well, she must be in one of the other rooms,” said Markhoff, stolidly, quite unmoved by his master’s fury. He went into one on the opposite side to the room where Jo and George crouched trembling. Then he came into their room, and at once saw the top of Jo’s head showing behind the chair.

He pounced on her and dragged her out. “Here she is!” he said, and didn’t seem to realize that it was not George at all, but Jo. With their short hair, freckled faces and their similar clothes they really were alike. Jo yelled and struggled most realistically. Nobody would have guessed that she had planned to be caught and locked up!