The next morning when Jack rushed to the window to look at the tower of the Old House he found that Mr. Diaz had kept his word - the window was now boarded up! No messages could be given to the prisoners, and they could send no messages back.

Jack didn’t like it. He had hoped that perhaps Mr. Diaz might have forgotten to block up the window. It made everything seem very serious, when he looked at that blind window with the boards across it.

The children went down to breakfast looking solemn. Nora gave a little sob when she looked at Mike’s empty chair at the table. But Dimmy seemed very cheerful and patted her on the back.

“Don’t worry,” she said. “Now that you’ve told me, I’ll do my best to help - and we’ll rescue both boys, never fear!”

Nobody seemed to want much breakfast, although it was poached eggs, which they all loved. Nora was anxious to do something for Mike and Paul as soon as possible, and she wouldn’t even let Dimmy wash up after breakfast.

“Please do let us see if we can discover the secret door out of our tower,” she begged. “Leave the cups and things, Dimmy dear - we can do those afterwards.”

So Dimmy left them, and the three children trooped up the winding stone staircase with her. They went to Jack’s room and looked round the grey stone walls.

It seemed impossible to find any secret door in those great walls. They knocked on them, they pressed on them, they stood on chairs and pushed against the higher part of the walls, but nothing moved, nothing swung round to show a hidden passage in the thick stone walls.

At eleven o’clock they stopped their hunting, quite tired out. Dimmy looked at Nora’s pale face, and was sorry for her.

“I’m going to make some cocoa for us all, and get some ginger cake,” she said. “We need a rest.”

She ran downstairs. Peggy went with her to help. Nora sat on Jack’s bed and looked gloomy.

“Cheer up, Nora,” said Jack.

“I’m quite, quite sure there’s no hidden door in this room,” said Nora, with a deep sigh.

“I feel as if there isn’t too,” said Jack anxiously. “Wouldn’t it be dreadful if it was only a tale, and not true at all!”

“Don’t, Jack,” said Nora. “You make me feel worse.”

Jack sat and thought for a few minutes. “I wonder if by any chance Dimmy has any old maps of Spiggy Holes in that big bookcase of hers downstairs,” he said. “If she had, one of them might show where the hidden door is.”

Dimmy came into the room at that minute, carrying a big jug of milky cocoa. Peggy followed with a dish of brown gingerbread. Everyone felt quite cheered by the look of it.

“Dimmy, I suppose you’ve no old books about Spiggy Holes, or old maps, have you?” asked Jack, munching his gingerbread.

Dimmy looked surprised. “Why didn’t I think of that before?” she said. “Of course! There are two or three old books about this place, belonging to my great-grand-father. I believe they are very valuable. They are locked up in the big bookcase downstairs.”

Jack almost choked over his cake in his delight. “Let’s get them!” he said, jumping up.

“Finish your cake and cocoa.” said Dimmy. “Then we’ll go downstairs and look for them.”

How the three children swallowed down their cocoa and gingerbread, in their eagerness to rush downstairs to find the old books! It wasn’t more than a minute or two before they were all in Dimmy’s rather dark little drawing-room, watching her whilst she unlocked the big old-fashioned bookcase there.

She moved aside some of the books on the top row, and behind them were some very old books, carefully covered in thick brown paper.

“There they are,” said Dimmy. “This one is called Spiggy Holes - a record of smuggling days. And this one is called Tales of Smugglers, and Spiggy Holes is mentioned several times. This one is only an old cookery book - and this is a diary kept by my grandfather.”

The children pounced eagerly on the first two books. The girls turned over the pages of Spiggy Holes, and Jack looked hurriedly through Tales of Smugglers.

“Look! Look! Here’s a map of the secret passage we know!” cried Peggy suddenly. All the others crowded round her and peeped at the book she was holding. She laid it flat on the table. She pointed to a page on which was drawn a small map, showing Peep-Hole and the Old House and the shore. From the shore-cave to the Old House the secret passage was shown winding its way through the cliff underground to the cellars of the Old House.

“But there’s no way shown from Peep-Hole to the Old House,” said Jack in disappointment.

He was right. There was no hidden path between the two houses on the map. Eagerly Nora turned the pages to see if another map was shown, but there was none.

The two books were a great disappointment. Peggy, who was a good reader, hurriedly read through both of them to see if she could perhaps find anything written about the way between the two towers - but not a word was said.

“It must have been just a tale,” said Nora in disappointment, closing the books.

“I feel sure it wasn’t,” said Dimmy, puzzled. “I remember so well how my grandfather told me about the secret. I wonder if he says anything about it in his old diary. He kept it when he was a boy, and it wasn’t found until a year or two ago. The ink has faded, and it was so difficult to read that I didn’t try more than a few pages. It was all about his days as a boy.”

“Dimmy, let me have it,” said Jack. “I will go away by myself and try to make it all out. It will take me a little time, but I’ll use my magnifying-glass to help me to read your grandfather’s tiny writing.”

Dimmy gave the little paper-covered diary to Jack. He slipped off upstairs with it. The two girls looked at Dimmy.

“What shall we do?” asked Nora. “I don’t feel like bathing or digging without Mike here.”

“Then you can just come and help me to wash up those breakfast things and make the beds and dust and get dinner ready!” said Dimmy briskly. “It will do you good to think of something else for a while.”

“It won’t,” said Peggy dismally. But Dimmy was right. Both girls felt much better about things when they set to work to wash up and to dust.

Dinner-time came. Peggy went up to fetch Jack. He was huddled in a corner with his magnifying-glass, trying to read every word of the old, old diary.

“Dinner-time,” said Peggy. “Have you found anything interesting, Jack?”

“No,” said Jack. “It’s all about how he goes birds’-nesting and fishing and boating. He must have been a nice sort of boy. He was a great one for playing tricks on people too. It says here how he put a toad into his aunt’s bed, and she woke the whole house up to get it out!”

“Naughty boy!” said Peggy. “And poor old toad! It must have hated being squashed under the bedclothes. What else does it say?”

“Oh, lots of things,” said Jack, flicking over the pages. “Tell Dimmy I’ll be down in half a minute. I just want to finish the next few pages.”

So Peggy went downstairs again, and Dimmy and the two girls began their meal without Jack. They were in the middle of it when they heard a tremendous shouting, and Jack’s feet came tearing down the stone staircase. The door into the kitchen was flung open, and then the dining-room door flew back with a crash. The girls almost jumped out of their skin. Dimmy leapt to her feet.

“Whatever’s the matter?” she cried.

“I’ve found it, I’ve found it!” yelled Jack, dancing round the room like a clown in a circus. “It’s all here - there’s a map of it and everything!”

The girls squealed. Dimmy sank down into her chair again. She wasn’t used to these adventures!

“Show! Show us the map!” yelled Nora. She swept aside her plate and glass with a crash, and Jack set the old diary down on the tablecloth.

“Listen,” he said. “This is Dimmy’s grandfather’s entry for the third of June, exactly one hundred years ago! He says, ‘To-day has been the most exciting day of my life. I found at last the old hidden passage between Peep-Hole and the Old House tower. A gull fell into the chimney of my room and I climbed up it to free the bird. Whilst I was there I pressed by accident on the great stone that swings round to open the passage in the wall of the tower.’ ”

“O-o-oh!” squealed Nora. “We can find it too!”

“Don’t interrupt,” said Peggy, her face pale with excitement. “Go on, Jack.”

“He goes on to tell how he got into the passage, which runs down the walls of our tower to the ground, up the cliff to the Old House, branches off to join our own secret passage somewhere, and also goes on to the tower of the Old House, up and inside the thick walls there, and into the topmost room of the tower!” Jack could hardly speak, he was so thrilled at having found what he wanted.

“There’s a rough map here that he drew after he had found out all about the passage. He kept the secret to himself, because he was afraid that if he didn’t his father might have the passage blocked up.”

Everyone pored over the map. It was faded and difficult to see, even under the magnifying-glass, but the children could plainly follow the passage from their tower, downwards in the wall right to the ground and below it, then underground to the Old House, up through the thick walls there, and into the top room of the Old House tower.

“I knew I was right! I knew I was right!” said Dimmy, quite as excited as the children.

“Let’s go straight up and find it!” said Nora. “Come on! Oh, do come on!”

They all fled upstairs, tumbling over the steps in their haste. They must find that secret door in the chimney. Quick! Quick!