“Father, are you all right? What’s happened — and where’s Timmy?” said George, urgently. She looked all round, but could see no sign of him. Her heart went cold. Surely nothing awful had happened to Timmy?

“Did you see two men?” asked her father. “Where were they?”

“Oh Father — we keep asking each other questions and not answering them!” said George. “Tell me first — where is Timmy?”

“I don’t know,” said her father. “Did those two men go to the tower?”

“Yes,” said George. “Father, what’s happened?”

“Well, if they’ve gone to the tower, we’ve got about an hour in peace,” said her father. “Now listen to me, George, very carefully. This is terribly important.”

“I’m listening,” said George. “But do hurry up and tell me about Timmy.”

“These two men were parachuted down on to the island, to try and find out my secret,” said her father. “I’ll tell you what my experiments are for, George — they are to find a way of replacing all coal, coke and oil — an idea to give the world all the heat and power it wants, and to do away with mines and miners.”

“Good gracious!” said George. “It would be one of the most wonderful things the world has ever known.”

“Yes,” said her father. “And I should give it to the whole world — it shall not be in the power of any one country, or collection of men. It shall be a gift to the whole of mankind — but, George, there are men who want my secret for themselves, so that they may make colossal fortunes out of it.”

“How hateful!” cried George. “Go on, Father — how did they hear of it?”

“Well, I was at work on this idea with some of my colleagues, my fellow-workers,” said her father. “And one of them betrayed us, and went to some powerful business men to tell them of my idea. So when I knew this I decided to come away in secret and finish my experiments by myself. Then nobody could betray me.”

“And you came here!” said George. “To my island.”

“Yes — because I needed water over me and water around me,” said her father. “Quite by chance I looked at a copy of that old map, and thought that if the passage shown there — the one leading from the little stone room, I mean — if the passage there really did lead under the sea, as it seemed to show, that would be the ideal place to finish my experiments.”

“Oh Father — and I made such a fuss!” said George, ashamed now, to remember how cross she had been.

“Did you?” said her father, as if he had forgotten all about that. “Well, I got all my stuff and came here. And now these fellows have found me, and got hold of me!”

“Poor Father! Can’t I help?” said George. “I could go back and bring help over here, couldn’t I?”