"He can't have just vanished," said Dinah.

"I suggest we have a look round the room as see if there are any hidden compartments or rooms to this building," said Jack.

"Okay, you and Lucy-Ann look over there, Jack. Dinah, you and I will search over in that corner and Philip I want you to see if you can climb up onto these rafters somehow." They all spread out. Jack was scanning the floor, which was littered in rocks and boulders. He felt sure that Big Charlie must have gone down a trap door. Bill gave Philip a boost onto the rafters and then started to tap the walls with Dinah.

"Be careful everyone, these walls look ready to collapse at any moment," said Bill. They hadn't been searching long when there was a loud crack from overhead and the beam that Philip was on splintered in two. He lost his footing and tripped. Lucy-Ann screamed and Bill rushed forward ready to catch Philip if he fell. However Philip did a clumsy leap forward and managed to heave himself up onto another beam.

"You all right Philip?" asked Jack. Kiki flew up to Philip, and walked along a beam towards him, looking for all the world as if she was concerned about his safety. "Pop goes the weasel?" she enquired.

Philip grinned at her. "I'm fine thanks, I'll be more careful from now on. I'll climb a bit higher, maybe he is hiding up there." Bill wanted Philip to climb down. He didn't feel the beams were safe to be climbing about on. Philip ignored him and climbed higher. They had been searching for nearly ten minutes when Jack found something.

"Hey, look what I've found!" he called excitedly. "It's a trap door, I bet that's where Charlie's gone." The others all crowed round him apart from Philip who decided he could see better from where he was.

"Err, its all covered in cobwebs," said Dinah backing off. "There are probably hundreds of them in here Dinah," said Bill. Dinah shivered and looked around.

"In fact, there's one on your shoulder Dinah!" cried Philip. Dinah screamed and shook her top.

"There's nothing there, Dinah," said Lucy-Ann. "Philip was just teasing."

"Philip," said Bill sounding a little annoyed. "Now's not the time."

"I know, sorry Bill. I couldn't resist." Jack was pulling at the trap door, which had an iron ring attached to it.

"It's jolly heavy," he said. "You have a go Bill." Bill took hold of the ring and braced himself. Then he game a huge heave and the door eased stiffly open. They all peered down. It showed a set of steep stone steps, leading down into the inky darkness.

"Wow, we found it," said Dinah excitedly and got out her torch.

"Wait," said Bill. "Listen." They all stood still and listened but could here nothing. Bill decided it would be safe to go down the steps and borrowed Dinah's torch and flashed it on. Jack also got out his torch, and followed Bill down the steps. Dinah and Lucy-Ann also followed a little apprehensively. Philip was just climbing down from the rafters when something in the corner of his eye caught his attention. He stayed still, hidden in the shadows of the roof. Someone was just outside the opening, to his horror he realised it was Big Charlie. Should he call down and warm Bill or should he just stay silent and watch? Before he could make up his mind, Big Charlie crept into the room, casting a look around the room, but not up towards Philip. Big Charlie moved stealthily towards the trap door, he glanced down it briefly, before slamming it shut with a crash that echoed round the little deserted room, making Philip jump. Big Charlie then dragged a fairly big boulder that was nearby on top of it. Philip watched in dread as he quickly dashed out to his truck and started the engine. Philip could hear the sounds of Bill trying to lift up the trap door with the boulder on top of it.

Philip watched as Big Charlie reversed his car, and was about to jump down when Big Charlie suddenly accelerated and purposefully drove into the side of the building at an alarming speed. In fright Philip felt the whole building shake and shudder and then the sound of shifting bricks. Dust and pieces of tile started to fall from the roof above his head. He crouched against the wall and covered his head trying not to breathe in the dust. The beam he was on swayed and then one side of the wall toppled and fell crashing to the floor, emitting a huge cloud of dust and bits of grit flew everywhere. Philip choked and nearly fell off its beam, but just managed to steady himself. When the cloud of dust had settled a little, Philip was completely caked in dust from head to foot. He could see that the bricks and boulders that had previously been the wall completely covered the entire floor, including the trap door. Philip just sat on his beam, stunned and shocked, with trickles of dust still falling from the roof. Big Charlie climbed out of his car, completely unhurt. His car wasn't even damaged. He made his way over to where the trap door had been and bellowed down to Bill.

"BILL, BILL CAN YOU HEAR ME? ARE YOU STILL ALIVE DOWN THERE?"

"Charlie!" came back the voice of Bill sounding very muffled.

"PITY," said Charlie. "I WAS RATHER HOPING YOU MIGHT HAVE BEEN SUFFOCATED. NEVER MIND. THERE'S NO WAY OUT OF THAT CELLAR. I'LL HAVE TO MAKE DO WITH THE FACT THAT YOU WILL ALL STARVE TO DEATH DOWN THERE."

"Charlie, let us out!"

"WHAT AND SPOIL ALL THE FUN? OH NO BILL, DOWN THERE YOU WILL STAY, AND THOSE DRATTED KIDS TOO!"

"How did you know we were here?" demanded Bill.

"OH I GOT A LITTLE PHONE CALL. THOSE KIDS MUST BE MAKING YOU SOFT, BILL. YOU CATCH ONE OF MY MEN, TELL HIM ALL ABOUT YOUR PLANS AND THEN LEAVE HIM WHERE HE CAN EASILY BE FOUND. YOU'RE LOSING YOUR TOUCH! GOODBYE BILL!" Big Charlie then walked out of the room, got in his car, reversed and drove away.

"Charlie, Charlie!" came the voice of Bill. Philip clambered down from his creaking beam and went over to where Bill's voice was coming from.

"Bill, it's Philip. Are you all alright?"

"Philip, thank goodness. We are all fine, are you hurt?"

"No, I was still on the beam. Charlie drove into one of the walls, it came crashing down and trapped you all."

"Has he gone?"

"Yes, he got back in his car and drove off. Hang on, I'll try and shift some of these rocks and get you out. I think…" Just then the roof collapsed. A beam fell and hit Philip on the head and he was instantly knocked out and covered in broken roof tiles and dust. Bill and the others below heard the colossal noise and backed off slightly as dust filtered down.

"Philip… PHILIP!" cried Bill. "ARE YOU ALRIGHT? PHILIP!" When he got no reply he felt faint in fear. He threw himself against the trap door desperately trying to open it. Lucy-Ann started to cry and Jack and Dinah looked at each other in terror.

"PHILIP!" cried Bill again in terror and still he got no reply.

Some time passed. Everyone down in the cellar felt too shocked to speak. They had known that the stone building was ready to collapse, and Philip had told them how Big Charlie has forced a wall down. The crash and resounding tremors that they had all felt down in the cellar left them in no doubt that more of the building had fallen, and they knew Philip had been standing just over the trapdoor when it had collapsed. Lucy-Ann felt even worse because Bill, who usually could reassure her and give her hope, was so obviously out of his mind with concern for Philip that she couldn't feel any optimism at all. Bill was repeatedly slamming his shoulder against the trapdoor above, in an effort to open it. Each time he did so small trickles of dust fell down onto them, illuminated in the torchlight, but the trapdoor did not seem to move a jot. There were just too many stones and beams piled on top of it. Eventually, Bill sank exhausted onto one of the stone steps.

Jack, feeling like he had to do something, followed the steps to the bottom and looked around the small cellar with his torch. It was empty, and having a good sense of direction Jack could tell that it did not extend beyond the walls of the building above. To keep his mind from thinking about what could have happened to Philip, he methodically examined each of the four walls and the floor, but found nothing. Kiki sat on his shoulder quietly, occasionally nibbling his ear. She could tell that something was upsetting Jack.

Jack returned to the others. Bill had his arm around Lucy-Ann, and all were sitting on the steps just below the trapdoor. Jack caught Bill's eye, but could think of nothing to say. He could only ask what they could do, and he knew that Bill didn't have an answer to that. Jack sat down beside them on the step, and racked his brains for something to do.

Something was tickling, around his stomach. It moved upwards, slowly, slowly. It brushed his neck, and now it was tickling his face, his nose. He sneezed.

Philip opened his eyes. His head was pounding painfully, and his body felt stiff. He tried to move, but could only move his right arm. He could feel a heavy weight on the rest of his body, particularly his left arm. Whiskers scuttled away into the rubble, startled by the sneeze. Philip was amazed that he had survived the roof fall. He lay still, getting his bearings. His face, at least, although covered in dust, was facing the sky, and not under the rubble. Thick dark clouds were quickly covering the blue sky, and the wind was getting up. A fat raindrop splashed onto Philip's cheek, then another fell into his ear. The rain spurred him into action.

Carefully he turned his head to the left. The large beam that had knocked him out was lying across his left arm. He raised his right arm across and tried to push the beam away. It was painful to move, his whole body felt bruised, but he knew he couldn't stay as he was. Little by little he managed to push the beam off, and he rubbed his sore arm thankfully.

The rain was falling harder now, making the dust that covered him turn to a sort of chalky mud. He pulled desperately at the tiles and bricks covering his lower torso. Luckily the bricks that had made up the roof were smaller than the ones used for the wall, or he would have been crushed for certain. Soon he was able to wriggle his body out of the rubble. He looked about for Whiskers, but he seemed to have gone completely. "Probably best for him," Philip thought. The rain was a drenching downpour, restricting his vision. He knew he would not be able to hear the others down below over the beating of the drops. Philip got to his feet, and winced at the pain in his right ankle. It had been hurt. He limped as fast as he was able over to their car, and got inside.

The rain beating on the windows prevented him from seeing anything outside. He used the rear-view mirror to check his face for injuries and was shocked to see a large, deep cut on his cheek. He hadn't even felt it. He found a bottle of water that he had brought with the food and cleaned his cut a bit, to get rid of the dust that was in it.

The rain was fortunately just a shower, and abruptly stopped as if someone had turned off a sprinkler. Philip got out of the car instantly and hobbled back to the pile of rubble that had once been the stone building. Only two walls were left standing. Philip eyed them nervously, but they seemed to be staying upright for the time being. He went over to where he remembered the trapdoor to be and shouted.

"Jack! Bill! Can you hear me?"

Down on the cellar steps, lit by a single torch, the others exchanged delighted looks. Bill leapt to his feet at once. "Philip! Are you alright?"

"I'm okay!" Philip shouted back. He could barely hear Bill's reply over the wind. "I'm going to try and move some of this rubble!"

He set to work, getting into a regular rhythm of bending down, grabbing a roof tile in each hand, and swinging them away from the trapdoor. He soon felt tired and his body ached all over, but he tried to ignore it and keep in the rhythm. Soon he had cleared all of the tiles and Philip was feeling pleased with his progress. He put his arms around a huge piece of stone that had been a wall brick and heaved. But the stone would not move. He pushed at it from the side, but although it rocked in its position, there was so much rubble around that he could not move it. Feeling defeated and exhausted, he sank down on the ground.

Bill's voice came up to him. "Philip, how are you doing?"

"I- I can't move the bricks," Philip said wearily. "They're too big. I don't know what to do."

There was silence for a minute. "Just have a break," Bill called back.

Philip sat on the ground for five minutes, suddenly feeling the effects of his accident after the hard work moving the tiles. He felt sleepy; he would love to go to sleep and wake up and find it was all just a dream…

The rain woke him from his drifting reverie. It was starting again. Philip willed himself into action. I can move the boulder, he thought, and before his body could realise otherwise he jumped to his feet and pushed at the stone with all his might. And it moved! Delighted, Philip moved two more bricks, and then he could see the outline of the trapdoor in the dust. With one last colossal effort he heaved at the boulder Big Charlie had originally put over the trap door to stop Bill getting out again, and then he sank to the floor. "All yours, Bill!" he called weakly.

Bill immediately began thumping against the trapdoor below, and with a small amount of effort pushed the trapdoor open. He went over to Philip anxiously, and examined him for injuries. "Are you alright?" he asked.

"Yes, I'm fine," said Philip bravely. "Just a bit knocked about. Are you all okay?"

Dinah, Jack and Lucy-Ann emerged from the cellar. Dinah and Lucy-Ann rushed and gave him a hug as Bill pulled Philip to his feet. "Oh, I'm so glad you are all right!" cried Lucy-Ann.

"If you hadn't been in the rafters we would all still be down there, starving to death," said Dinah with a shiver.

Jack gave Philip a grin and clapped him on the shoulder. Philip winced, as it was sore. "Sorry," said Jack.

Bill was still looking concerned at Philip as if unable to believe that he was okay. "Right," he said eventually. "Come on, let's get out of here."

They walked slowly to the car. Big Charlie was gone, where to was anyone's guess. There was no hurry. There was a sharp crack as Dinah put her foot down. She raised her foot in surprise, bent down and picked up a black audio cassette tape from the ground.

"Look at this," she said, puzzled.

Jack took it from her. "I shouldn't think many people have been here recently," he said excitedly. "Maybe Big Charlie dropped it!"

He handed it to Bill, who examined it closely. "You've cracked the casing when you stepped on it, Dinah, but it might still work. That is, it may if it wasn't so wet." He shook it vigorously to empty it of rainwater. "Let's try it in the car."

They hurried over to the Landrover, which fortunately Big Charlie had not damaged before he left, apparently presuming they would never get out of their cellar prison.

They got in, and Bill started the engine and put the tape into the slot. They all leaned forward, eagerly. There came the low hiss that cassette tapes give when playing. Suddenly, to everyone's astonishment, Bill's voice came over the speakers. Then came another voice in reply. The children looked at Bill, whose expression was as startled as they felt.

"It sounds like a telephone call," said Jack.

"That's exactly what it is," said Bill. He was beginning to look angry.

"What is it about?" asked Dinah.

Bill pursed his lips. "It was a phone call to one of the members of my team, discussing the surveillance we were doing on Big Charlie. No wonder the trail we were following suddenly dried up, somehow he had tapped our phones and heard our conversation. That's how he knew I was on to him. He's cleverer than we had thought."

Bill fast-forwarded the tape a bit, and played it again. His own voice rang out again, this time as a radio transmission. Bill gave an angry exclamation. "He intercepted our radio broadcasts as well! Those were encrypted. It's no surprise he's cleaning up his operation after he knew all this." He stopped the tape.

"Aren't you going to listen to the other side?" asked Dinah.

"It'll be more of the same," said Bill shortly. He was obviously annoyed that Charlie and his gang had been able to intercept his messages. He should have picked up on the fact that their communications weren't secure. If he had, all this wouldn't have happened.

"You don't know that," said Jack, and he reached over and ejected the tape, and turned it over. He pressed play. A garbled voice spoke back at them, in a voice that hardly seemed human. It certainly didn't sound like any language Jack had ever heard. Kiki was startled. "Pop goes the Queen," she said. "Oh I say!" But Bill came alert again at once.

"Aha!" he exclaimed. "This is a clever audio code they've used before, and we have enciphered it. You have to just listen to the bleeps in the background, the rest is just random meaningless sounds. Give me some paper and a pen, someone." He rewound the tape. Lucy-Ann handed over a notebook and a pen.

Everyone was quiet as Bill played the bizarre sounding message again, watching as he made marks on the piece of paper in front of him. When the tape came to an end, Bill began scribbling rapidly on the notebook. Soon he looked up. "It says, 'Windy Top until died down'," he said. "It's a strange message - it could mean anything really - but Windy Top is a hill not far from here." He put the car into gear. "It's the only clue we've got, and I don't want to give up now. Are you all still up for more adventure?"

"Of course we are!" cried Jack. "Right the first thing to do is to see if there is a map in this car," said Bill. "I have heard of Windy Top but I'm not sure where it is in relation to here." They all had a little hunt around and Jack found one under his seat. He passed it to Bill who studied it. After some consideration he worked out where they were at the moment and found out that Windy Top was around 50 miles away.

"It should take us just under an hour to get there," said Bill. "I just need someone to read the map for me."

"I'll do it," said Dinah and took the map from Bill. Bill started the car and headed back down the bumpy track. When the reached the road again Dinah was able to direct him the right way. They talked quietly among themselves for a little while. Jack was sitting in the front with Bill and the others were in the back.

"What do you think, Philip?" asked Jack.

"Shh Jack, Philip's asleep," said Lucy-Ann. Bill glanced behind him and saw Philip slumped against the side of the car in a deep sleep.

"Do you think we should let him sleep?" asked Jack. "What if he has concussion or something?"

"Oh I think it will be alright," said Bill. "He's just tired out, he deserves some sleep, don't disturb him. Where do I go now Dinah?"

"Left, until the roundabout, then straight on," said Dinah. As they travelled it grew darker and darker. The thick black clouds that had been around all day, made the night come early. Bill was pleased; this meant they wouldn't be so easily spotted when they reached Windy Top.

After fifty minutes of travelling, they were nearly there. Dinah said they only had two more bends to go. By this time Philip had woken up again and was feeling a lot more cheerful, and happily joined in the conversation. Bill decided it would be wise to switch off their headlights and to slow right down to try and avoid detection.

"At least the car is black," said Lucy-Ann. "We blend in a lot more now."

"Right everyone, I want you to quiet from now on. I want to be able to concentrate," said Bill. They all instantly fell silent and started to feel excited. As the rounded the last bend a tall, steep hill appeared before them. Bill debated whether to drive up the hill or to get out at the bottom and walk. In the end he decided it would be wisest to walk up. They didn't know what they find up on the hill, or if there was anyone guarding the road. If there was, they would then be in a tricky situation. Bill parked the car next to a clump of trees, and turned to look at the children.

"Right, I think it would be wisest to get out and climb up this hill rather than drive up it. I would suggest you all stay here while I go and have a look, but I know you wouldn't let me. So come on, everybody out, and Jack, make sure Kiki keeps absolutely silent." They all clambered out of the car and started to walk cautiously up the hill. Bill kept a sharp ear out for anyone ahead of them, but could see nor hear no one. The hill was very steep and due to all the recent rain it had become muddy and slippery. They all kept on slipping back a few paces every so often, but luckily no one fell. When they were nearing the top they could see a light being shone out from what looked like a little hut. As they drew nearer they found out it was a sentry post with a barrier stretching across the road. A man stood beside the hut, obviously on the look out for any approaching cars and Bill felt thankful that they hadn't driven up. They walked away from the hut before continuing on up the hill, they didn't want to be spotted. They were now very near the top of the hill and a strong gusty wind had blown up. They all found themselves shivering and Jack had to put Kiki up his jumper to stop her from being blown off of his shoulder.

Bill signalled to them stop a few metres before the peak of hill, which seemed to level out at the top. They could now see a great amount of bright light being admitted by a large building, built on top of the hill itself. Bill crept up to the top of the hill on his own and had a brief glance around. There was no one in sight, although he could now hear the sound of machinery coming from the large building. He waved the others up and told them in whispers to look for somewhere to hide. They crept cautiously around, keeping as far away from light as possible. They didn't want anyone looking out of a window to spot them. Dinah saw it first, a fairly large wooden shed, a few yards from the main building. She nudged the others and pointed it out. They all crept towards it, and Bill peered in at the windows before trying the door.

"It's no good, its locked," he said. Lucy-Ann, who was at the back of the group, noticed something glinting in the moonlight on the side of the shed. She went towards it and found it to be a key hanging on a little hook. She took it to show the others excitedly.

"Here, try this key, it was on the side of the shed hanging on a nail." Jack took it and tried it in the lock. The lock clicked and they were able to open door.

"Well done Lucy-Ann," said Philip. "They obviously don't expect many visitors." Bill ushered them all inside the door, took the key from Jack and locked them all in from the other side.

"Windy Top is certainly a good name for this place," said Dinah.

"Yes, you can see how it got its name," said Jack. "I thought I was going to be blown right down the hill at one point." He took Kiki from his jumper. She was relieved to be out, and sat on his shoulder making affectionate noises in his ear.

"Let's find somewhere to sit down," said Philip. They all felt around and found the shed to be full of machinery, covered in blankets.

"Pull these blankets off and sit on them," said Bill. "We might as well be comfortable. Well this looks like the place alright."

"Whatever is it?" asked Lucy-Ann. "I couldn't make it out."

"It looked like an aerodrome to me," said Jack. "You know, the places where they store planes when they are not being used."