With that, he reached down and picked up a long, wet plank from the debris along the shore. He put it on his shoulder and glanced at his companions.

Bob and Pete smiled weakly. Then, with resolutely set faces and quaking hearts, the boys walked slowly towards the dark opening in the face of the cliff.

They crossed the slight ridge near the waterline, scanning the sand each foot of the way. Suddenly Jupiter stopped. His eyes were bright.

“Here’s something,” he said softly.

Bob and Pete looked down. There were unmistakable depressions in the loose soft sand.

“This dragon must be a new type,” Bob said finally. “It looks like it’s running on wheels.”

Jupiter nodded. He looked up and down the beach. “I don’t see anything. But these look like the tracks of some kind of vehicle. Maybe a beach buggy. Some times lifeguards use a jeep or beach buggy to patrol a long area, such as this.”

“Maybe,” Bob said. “But if they were on patrol, these tracks would be heading north and south — the way the beach runs. Instead, they’re heading towards the cave.”

“You’re right, Records,” Jupiter said. He dropped to his knees and studied the depressions.

Bob was scowling, looking back at the water. “I don’t get it. If the tracks show here, why couldn’t we see them near the water?”

“A heavy running tide and high breakers would wash them away, I guess,” Jupiter said.

Pete grinned. “I guess old Mr. Allen’s eyes aren’t too reliable. Instead of a dragon, what he probably saw was a jeep or something.”

“Possibly,” Jupiter answered. “In any event, when we get to the cave we’ll find out one way or the other.”

Ten yards from the cave, the tracks disappeared completely.

The boys looked at each other.

“Another mystery,” Pete said.

They reached the mouth of the cave. It looked empty.

“This opening is almost big enough for a bus,” Bob said. “I’ll take a look inside and see how far back it goes.”

Jupiter peered inside the cave. “All right, Bob. But stay within shouting distance. Pete and I will be with you, as soon as we check the entrance for any clues.”

Bob brandished his spearlike weapon and walked into the cave.

“What makes him so brave, all of a sudden?” Pete asked.

Jupiter smiled. “Once we saw the tracks were made by a man-made vehicle, rather than a fantastic creature such as a dragon, I think we all got a lot braver.”

He cocked his head, as if listening.

“Perhaps we can tell from the echo of Bob’s voice how large the cave is.” He raised his voice. “Just checking, Bob — how are things in there?”

Pete inclined his head, too, in a listening attitude. They heard the sound together. A heavy plopping sound.

Then they heard Bob’s voice. It was thin and high-pitched. He spoke only one word but it filled them with terror.

“Help!”

As Jupiter and Pete stared wide-eyed into the dimly lit cave, they heard Bob cry out again.

“Help! Help me!”

“Bob’s in trouble!” Pete exclaimed. “Come on!”

Pete, the most muscular and athletic of the trio, darted into the cave. Jupiter tried to keep up with Pete’s flying feet.

“Not so fast, Pete,” Jupiter said. “He’s not too far away, and we have to be careful not to — ”

He never completed his sentence. In the gloom of the cave, he suddenly ran into something hard that knocked the wind out of him. He fell to his knees.

Then he heard Pete’s voice.

“Stay back, Jupe! I’ve found him!”

“Where, Pete? I can’t see.”

Jupiter blinked. Then his eyes adjusted to the darkness of the cave. He saw Pete was on his hands and knees in front of him.

“He’s down a hole,” Pete said. “I stopped just in time.”

“I can’t see,” Jupiter said. He tried to peer around Pete’s shoulder. “Bob,” he called. “Where are you?” Bob’s voice was so close, he jumped.

“Down here!” Bob cried. “I fell into some kind of a pit. It seems to be dragging me down!”

“Yipes!” Pete exclaimed. “Quicksand!”

“Impossible,” Jupiter said. “Quicksand is usually found in tropical countries.”

He wriggled round Pete, carefully feeling the cavern floor with his hands. “I still can’t see him. Bob, can you see us?”

“Yes,” Bob said. “I’m almost directly under you.”

Jupiter leaned over, extending his arm. “Just reach up and grab my hand, Bob. Pete and I will pull you out.”

They heard dull plopping sounds below.

“I c-can’t!” they heard Bob say after a moment. “Whenever I try, I seem to sink deeper!”

“Push your stick up,” Pete suggested. “That broken oar you were holding. Jupe and I could pull you out in a second.”

“I can’t”, Bob said despairingly. “I dropped it when I fell in here.”

Pete looked at his piece of driftwood and groaned. “Mine’s too light to hold you.”

Jupiter was wriggling cautiously round the edge of the pit. “Hang on, Bob,” he said. “I’m circling the pit to try to get some idea of its size.”

He crawled slowly away.

“Hurry!” Bob cried. “This is no time for measuring things.”

“I’ve got to,” Jupiter replied. “It’s the only way I can think of to get you out.”

He made his way in the darkness on his hands and knees. Bits of earth dropped into the pit, despite his care.

“Watch it!” Bob cried out. “You’re starting a landslide!”

“Sorry,” Jupiter said. “It’s the loose dirt round the edges.”

In another moment, he had completely circled the pit and rejoined Pete. “I think we can manage it.” He called down to Bob again. “Bob, can you tell us if you are touching bottom?” They heard thrashing sounds below. Then spluttering, spitting noises.

“Not yet,” Bob replied testily. “Maybe by the time you geniuses up there think of a way to get me out, I will be.”

“If you hold my legs, Jupe, I can reach down for him,” Pete said. “We don’t have time for anything fancy.”

Jupiter shook his head. “I think we can use my plank. Not for pulling him out directly — we’d never get enough leverage on this sandy ground. But the plank is just long enough to reach across the pit and wedge into the sides.”

“Then what good is that?” Pete asked. “Bob can’t reach that high.”

“Yes he can, if we can place it at the right angle,” Jupiter said. “I think we can wedge it in from the opposite side.”

Pete looked at the thin plank Jupiter held. He nodded, wetting his lips. “It’s worth a try. If it will hold his weight.”

Jupiter leaned over the ledge. “We’ll be trying to reach over your head, Bob,” he explained. “It will be up to you to see that the plank is wedged in firmly enough to sustain your weight.

“Because if it slips,” he added, “we’ll not only lose the plank, but you.”

“Thanks a lot,” Bob answered. “Only hurry it up. I think I’ve sunk another couple of inches.”

Jupiter left Pete and hurried to the far side. He leaned over the edge and extended the plank.

“I’m pushing it out now,” he told his friends. “I don’t know if you can see it, Bob. But in a moment it should be passing over your head.”

Lying on his stomach, he shoved the plank out foot by foot. Finally he heard a shout from below.

“I can see it now,” Bob called. Then, on a higher despairing note, “I can’t reach it. It’s too high.”

“It’s coming down now,” Jupiter said. “I’m trying to get the precise angle where it will fit.”

He extended the plank a few more inches.

“You’re doing fine, Jupe,” Bob called. “It’s coming in all right. Just another couple of inches,”

He waited for Jupiter’s next move. Then he heard a scuffling sound. “Come on, Jupe. What’s holding you up?”

Jupiter’s voice was hoarse. “I’m out too far. I–I’m beginning to fall in myself!”

“Oh, no!” Pete groaned. He leaped to his feet and dashed for the other side.

Jupiter’s feet were clawing wildly for purchase on the slippery ground. The rest of him was already tilted downwards over the dark pit. Bits of earth crumbled under his weight and rolled away.