Timmy squeezed out of the space left. He flung himself on George, who fell on the ground with her arms tight round him. He licked her face and whined, and she buried her nose in his thick fur in joy. “Timmy! What have they done to you? Timmy, I came as soon as I could!”

Timmy whined again and again in joy, and tried to paw and lick George as if he couldn’t have enough of her. It would have been difficult to say which of the two was the happier.

At last George pushed Timmy away firmly. “Timmy we’ve got work to do! We’ve got to escape from here and get across to the mainland and bring help.”

“Woof,” said Timmy. George stood up and flashed her torch into the tiny cave where Timmy had been. She saw that there was a bowl of water there and some biscuits. The men had not ill-treated him, then, except to lasso him and half-choke him when they caught him. She felt round his neck tenderly, but except for a swollen ridge there, he seemed none the worse.

“Now hurry up — we’ll go back to Father’s cave — and then find another cave beyond his to hide in till the two men come back from the tower. Then we’ll creep out into the little stone room and row back to the mainland,” said George. “I’ve got a very, very important book here in my pocket, Timmy.”

Timmy growled suddenly, and the hairs on the back of his neck rose up. George stiffened, and stood listening.

A stern voice came down the passage. “I don’t know who you are or where you’ve come from — but if you have dared to let that dog loose he’ll be shot! And, to show you that I mean what I say, here’s something to let you know I’ve a revolver!”

Then there came a deafening crash, as the man pulled the trigger, and a bullet hit the roof somewhere in the passage. Timmy and George almost jumped out of their skins. Timmy would have leapt up the passage at once, but George had her hand on his collar. She was very frightened, and tried hard to think what was best to do.

The echoes of the shot went on and on. It was horrid. Timmy stopped growling, and George stayed absolutely still.

“Well?” said the voice, “Did you hear what I said? If that dog is loose, he’ll be shot. I’m not having my plans spoilt now. And you, whoever you are, will please come up the tunnel and let me see you. But I warn you — if the dog’s with you, that’s the end of him!”

“Timmy! Timmy, run away and hide somewhere!” whispered George suddenly. And then she remembered something else that filled her with despair. She had her father’s precious book of notes with her — in her pocket! Suppose the man found it on her? It would break her father’s heart to know that his wonderful secret had been stolen from him after all.