Jack looked at his watch. “It’s getting late,” he said. “We’ll go back to the beach and eat our dinner there. Come on! We don’t want to eat in this dark, dismal room!”

They went back to the secret passage. It was easier going down it than up. Bending their heads down every now and again the children made their way down it, stumbling over the rough, rocky path underfoot. Nora’s torch had no more light showing in it, so she walked close behind Jack, trying to see by the light of his.

At last they came to the cave that was over the shore cave. The rope hung down through the hole that led to the steps down the cave-wall. Jack got hold of it. He began to climb down - but he hadn’t gone far before he gave a shout of dismay.

“I say! What do you think’s happened?”

“What?” cried everyone anxiously.

“Why, the tide’s come in whilst we’ve been exploring, and the shore cave is full of water!” shouted Jack. “It’s almost up to the roof of the cave. We can’t possibly get down this way.”

He climbed back into the cave above. The children looked at each other gloomily by the light of their torches.

“What idiots we are!” said Mike. “We never thought about the tide. If we had thought we’d have known it was coming in and that we’d be nicely caught by it. It won’t be out of this cave for ages.”

“What are we going to do?” said Nora. “I’m so hungry. Can’t we eat our dinner now?”

“It’s damp and cold here,” said Jack, with a shiver. “We shall all get chills if we sit in this cave. We’d better go back to that underground room. At least it’s dry there. We can light our candles and eat our food by their light. Our torches won’t last much longer if we use them such a lot.”

So back they toiled up the secret passage till they came to the underground room. And there, where many a time the smugglers had sat and feasted and smoked, the four children undid their kit-bags and took out all the delicious things that Dimmy had put in for them.

Veal and ham pies had never tasted quite so good! And as for the ginger cake, the children could have done with twice as much! They finished up every scrap of everything, hard-boiled eggs and all, and then drank the sweet lemonade.

“That’s better,” said Jack, grinning round at the others by the light of four shining candles. “I was hungry.”

Mike looked at his watch. “It’s four o’clock,” he said. “I don’t suppose that cave will be clear till at least half-past five - and even then the beach is washed by huge waves that might sweep us off our feet. What a bore!”

“I’m simply longing to have a look at the tower of the Old House from the window of our tower,” said Nora. “I do want to see who the prisoner is. Wouldn’t it be lovely if we could rescue him!”

“Jack, couldn’t we escape through the grounds straightaway now?” said Peggy. “If we went up into the cellars again, and into the scullery, and down the tradesmen’s entrance to the back gate we could easily get home in ten minutes - instead of waiting for hours for the tide to go out of the cave!”

“Well, we’ll have to be jolly careful,” said Jack, who also didn’t want to wait for hours for the tide. “I’ll go first as usual and see that all’s clear.”

They all went up the eighteen steps into the cellar. Jack slipped up the steps to the scullery. No one was there. He could hear voices in the kitchen, but he guessed that the maids there were having their tea.

Everything was quiet. Jack gave a low whistle and the others came up the steps quietly. They tiptoed to the back door, where a row of empty milk-bottles stood, waiting for the milkman.

And then they saw something that filled them with dismay! Two big Airedale dogs were roaming about the garden!

“Look!” whispered Jack. “They’ll never let us pass. I’d forgotten that they’d got dogs to guard the place.”

Nora looked as if she were going to cry. First it was the tide that stopped them - and now it was two dogs.

“Do you think they’d hurt us if we tried to slip out of the grounds?” said Peggy.

“No,” said Jack, “but they’d bark the place down, and we’d be found at once. Wait a minute whilst I think what to do.”

“Ay, ay, Captain!” said Mike. The others waited obediently. Jack was always good at thinking of ideas when they were in a fix.

“I know what,” said Jack at last. “We’ll go into this little wash-house here and hide behind that heap of sacks. They must call in the dogs when a tradesman comes, or they wouldn’t get any goods. Well, we’ll wait till someone comes - the milkman or the baker - and as soon as the dogs are called in, we will slip out! We won’t go down the back path, we’ll make for that tree over there and climb it. I believe we could drop on to the top of the wall from its branches and get down the other side quite safely.”

“Good idea!” said Mike. They all crouched down in the little wash-house, first of all shutting the door so that no dog could wander inside and find them.

They waited. Jack sometimes popped his head up and peeped out of the window, but no one came. Then they heard the rattling of the milk-cart down the lane and Jack grinned at the others.

“Be ready,” he whispered. The milkman got down from his cart and rang a bell at the back gate. At once the two dogs set up a terrific barking. Luiz appeared round the house and called them. He tied the dogs to a tree and shouted to the milkman.

“All right! The dogs are tied. You can come in.”

The milkman went up the path with some bottles and some butter. A voice came from the kitchen. “Come right in, please.” He disappeared inside the scullery.

“Now’s our chance!” whispered Jack. “Luiz is gone. The dogs are tied. Run!”

The four of them ran through the wash-house door and sprinted across the grass to the tree that Jack had pointed out. The dogs saw them and began barking again, pulling at their leads as if they would break them.

“Lie down and be quiet!” yelled a voice from somewhere around the house. The dogs went on barking - but in a minute or two the children were safely up the tree, hidden in the branches. Still the dogs went on barking and barking.

Luiz appeared again, and shouted at them. “Quiet, I tell you!” he yelled. “It’s only the milkman!”

But the dogs knew that it wasn’t and they barked till they were hoarse. The children waited till Luiz had gone again and then one by one they climbed from a branch to the top of the wall, and dropped down to the other side in safety.

How glad they were! How they tore down the slope to Peep-Hole, giggling as they went. What an adventure they had had!

“Secret caves and passages, and finding a prisoner, and nearly getting caught ourselves!” panted Mike, as they reached Peep-Hole. “It’s all too exciting for anything!”

“And now we’ve got to find out who the poor prisoner is,” said Nora. “That’s what I’m longing to know!”

Dimmy met them in the hall. “So you’re back again,” she said. “Did you have a good picnic? What a lovely sunny day it has been, hasn’t it?”

“Has it?” said the children, trying to remember - but all they could remember was darkness and dampness in the secret passage and caves and cellar! “We really didn’t notice if the weather was sunny or not, Dimmy!”

“What nonsense you do talk!” said Dimmy. “Go and get ready for tea. I’ve got you the last of the big red eating gooseberries out of the garden!”

“Good old Dimmy-Duck!” yelled Mike, and he tore upstairs to wash - but before he washed he went to his window to look across at the tower window of the Old House. When would he see somebody looking out there?