“We’re going to leave the bikes here and walk,” Jupiter explained. “We’ll try to keep out of sight.”
“Where do we walk to?” Pete wanted to know.
“I just noticed that this road curves around Devil Mountain towards the sea,” Jupiter explained. “I want to see if there is another entrance on the ocean side.”
Bob and Pete followed Jupiter down the dark road. The valley was shadowy in the moonlight. Shapes seemed to loom up out of the night as they walked — trees and boulders and dark gullies.
“There are three puzzles that have come to our attention to-night,” Jupiter said as they walked. “First, why did the moaning stop when we were inside the cave? I noticed that the wind was still blowing when we came out, so it wasn’t the wind that changed.”
“You mean something else made the moaning stop?” Bob asked.
“I’m sure of it,” Jupiter said firmly.
“But what?” demanded Pete.
“Perhaps something or someone who saw us,” Jupe replied. “Second,” he went on, “it seemed to me that Ben Jackson really wanted us to get out of that cave. I wonder why?”
“The way he changed was spooky,” Bob said, and he shivered, as if to prove it.
“Yes,” Jupiter mused, “he is a most peculiar old man. It almost seemed as if he was two different people living in two different times. In fact, I couldn’t help feeling that he was putting on some kind of performance.”
“Maybe he was really worried about us, Jupe,” Pete said. “I mean, if he really has seen… The Old One.”
“Perhaps,” Jupiter agreed. “And that’s our third problem — the black, shiny thing you saw, and those marks on the cave floor. I’m sure they were water marks. Of course there may be a pool in the cave, but it’s also possible that there’s another entrance to the cave on the ocean side. And that is what we’re going to look for!”
After the boys had walked a little farther, the road ended abruptly at an iron gate. Beyond it, two narrow paths, one to the left and one to the right, led down the rocky cliff. Far below, a white line of surf glowed in the moonlight. The boys climbed the fence and looked down over the steep cliff.
“We’ll go to the right, towards the cave,” Jupe said. “Pete had better lead and I’ll come last. We’ll rope ourselves together the way mountain climbers do. Then if we come to any difficult places, we’ll cross them one at a time.”
The boys quickly roped themselves together at their waists, and Pete led the way down the narrow path. Below, the sea surged in and out among giant black rocks made silvery by the moonlight. At low points on the path, spray flew up to drench the boys. Three times they had to turn and face the cliff to inch across narrow ledges.
At last the path led sharply downwards and they found themselves on a small white-sand beach. The beach was deserted now, but there was considerable evidence that people had been swimming there — empty beer cans, soft-drink bottles, and the remains of picnic lunches.
“We’ll look all along the cliff for some form of opening,” Jupiter decided.
The cliff face was heavily overgrown with scrubby bushes and stunted trees, and hidden in many places by large boulders. With their lights the boys searched behind the bushes and boulders. But they found no entrance to the cave.
“I think we’re looking in the wrong place, Jupe,” Pete said.
“Where else is there to look?” Bob asked.
“Well,” Pete explained, “no one has told us about another entrance. If there is one, I’ll bet it’s hard to get to.”
“You mean it’s not here on the beach?” Bob asked. “But it has to be near here because that path is the only way down.”
“I think you’re right,” Jupiter said. “Bob, you come with me. We’ll search on the right side. Pete, you go left.”
The rocks bordering the beach were slippery with seaweed and mussels so Jupiter and Bob had to pick their way cautiously. Jupiter kept his flashlight aimed at the cliff face in order to look for an opening.
Finally, they reached a point where they could go no farther unless they plunged into the water. Discouraged, they were turning back when they heard Pete shout.
“I found it!”
Bob and Jupiter scrambled over the wet rocks and ran pell-mell down the beach. At the far end, Pete was standing on a big flat rock. Between two giant boulders, they saw an opening in the cliff face. It was a small opening, and only a foot above the sea.
“I can hear the moaning again,” Pete said. “Listen.”
There was no mistaking the sound.
“Aaaaaahhhhhh — oooooooooo — ooooo — ooo!”
It floated out of the opening, very faint as if from deep inside the cavern.
Pete shone his flashlight into the entrance. It was black, wet and very narrow. The tunnel seemed to bore directly into the cliff face as far as they could see.
“It’s awful narrow and dark, Jupe,” Pete said uneasily.
“Maybe it doesn’t go anywhere,” Bob speculated.
“No,” insisted Jupiter. “It must go into the cave or we wouldn’t hear the moaning.”
“It sure looks small,” Pete said doubtfully.
Jupiter squatted and peered into the opening. “I think we can enter safely if we’re careful. Bob, you’re the smallest so we’ll tie the rope to you and you’ll go in first.”
“Me? All alone? I thought we were all going to go in together.”
“That would be the wrong way to do it, Bob,” Jupiter explained. “When entering an unknown passage, the correct way is to send one person in, with a rope on him, while the other two remain outside ready to pull him out instantly if he encounters any danger.”
“Sure,” Pete added. “In those prison camp films, when the soldiers dug tunnels to escape, they always tied a rope to the man who was inside the tunnel. If he pulled once on the rope they hauled him out.”
“Exactly,” Jupiter said with a trace of annoyance. The First Investigator did not like to have anyone suggest that his ideas were not original. He turned to Bob. “Remember, pull hard on the rope if you get into any trouble. We’ll pull you out.”
Somewhat unconvinced but game, Bob tied the rope firmly around his waist. Cautiously he crawled into the narrow tunnel.
Inside it was dark and cold. The ceiling was much too low for him to stand up, and the walls were wet and slimy with green sea moss. He had to inch along on his hands and knees. As he crawled slowly forward, beaming his flashlight ahead, crabs scuttled away, their claws scraping on the damp rock.
After Bob had gone about thirty feet, the ceiling suddenly inclined sharply upward. He stood up. His flashlight beam showed that the tunnel still led straight ahead, but it had become wide and dry, and angled upward.
“Jupe! Pete! It’s okay,” he called back into the tunnel.
Soon both Pete and Jupiter were standing beside him.
“It’s all dry here,” Pete observed.
“This part must be above the high-tide mark,” Jupiter said. “I’ll start marking our trail, and you and Bob listen for the moaning so we can go in the right direction.”