At intervals, Grumper tinkled the bell. When the boat came quite close, he suddenly stripped off his ghost costume and flung it aside. Then, still clutching the precious bell, he crept forward.

Nancy now could see that the man in the boat was Amos Hendrick. Presently he tied up his craft and stepped onto the rocky ledge. As he did so he saw the half-crouched figure.

"Grumper!" he exclaimed. "So we meet at last!"

"Yes, you trailed me to Candleton, but it will do you no good!" the little man cried out.

"You're wrong," retorted A. H. His eyes gleamed as he looked at the bell. "I won't haggle over price, but you'll sell it to me or go to jail!"

Grumper chuckled evilly. "That's impossible. You couldn't get the police if you tried. It's too late! The hour of doom is upon you! The bell is mine! I will taste revenge for what your father did to my father!"

"Grumper, you're crazy! My family always treated your father with more respect and consideration than was his due. The truth is, he robbed my grandfather while working in his forge! Now give me the bell!"

"Neither of us will live to keep it," the elfin man retorted, backing away. "It will disappear, just as the ghost who has frightened folks away from this cave will vanish forever!"

"You're talking wild! Give me that bell or I'll take it from you. I have three times your strength, Grumper."

"You may seize the bell, but you'll drown! Any moment now the ocean will rush through this cave!"

Nancy, knowing that the threat was not an idle one, called frantically from the stone stairway:

"A. H.! A. H.! It's true! The tide will turn any minute! We must all get out of the cave before it's too late!"

The old man looked at the girl as if she were a ghost. "Nancy Drew! How did you get here?"

"Never mind! We're all in danger!" Nancy cried. "Follow me up these steps!"

Grumper snarled at the girl and barred the man's path.

"You'll have to fight me to get past here!" he chortled. "Anyway, it's too late! I can hear the water now!"

Hopping about gleefully, the crazed man swung the bell. A. H. pushed him aside and dashed for the steps. Grumper laughed wildly.

"The waters will swirl to the very top of the cave stairs!" He chuckled. "And the door to the lab locks itself from the outside."

"Quick, you fool!" Hendrick cried. "Give us the key!"

"I threw mine away! We'll all die here together!"

Nancy and A. H. were frantic. Although escape seemed impossible, they started up the steps. Grumper trailed them, gloating over his enemy's predicament. When they reached the top, A. H. stood gasping for breath as Nancy turned to Grumper.

"Why don't you try to save yourself?" she urged, hoping that he might know some other way out of the cave. "Your boss didn't ask you to give up your own life."

"That guy who calls himself Monsieur Pappier and Mr. James and half a dozen other names will no longer be my boss." Grumper laughed mirthlessly. "His real name is Harry Tyrox, and he's a trickster and a cheat. Why, he even tried to steal my jeweled bell and sell it to Hendrick. When I found him out, he bargained with me to share the money I'd get for it. But I've outwitted him! I'll take the bell with me to the bottom of the sea!"

"We must get out before it's too late!" Nancy called frantically.

"So that's what upset you?" Nancy managed to speak soothingly as she tried desperately to gain their freedom. "You thought Tyrox intended to take the bell. Just lead us out of this trap and we'll have the police put that man behind bars."

"It's no use," Grumper replied in a calmer voice. "I have no key and the secret door is locked."

"Then we really are trapped here?" Nancy asked, losing heart for the first time.

"Yes, we're trapped. I'm sorry you have to go, too. When you first came to the cave I tried to frighten you away, and later that day I hoped to scare you with sleeping-gas fumes. But you wouldn't leave me alone, so you must suffer too."

At that instant in the cavern below they heard a faint, gurgling sound.

"The water is starting through," Grumper said. "In a moment it will come with a rushl"

In desperation Nancy pounded on the heavy secret door, but succeeded only in bruising her fists.

"Help! Help!" she called weakly.

Then suddenly Nancy wondered if her mind was playing a cruel trick on her. From behind the door had she heard footsteps and a m.u.f.fled voice?

CHAPTER XX.

The Bell's Secret

FRANTICALLY Nancy pounded on the heavy door. Again she heard the m.u.f.fled voice on the other side, but could not make out the words. Maybe the person was asking where the secret door was.

"The bench!" she cried. "Pull on the bench!"

At that moment the tolling of the bell reverberated throughout their rocky prison, followed by a thunderous roar as the surf from the ocean rushed into the cave. Drenched with spray, Nancy and the two men clung to the wall. As the noise subsided, they saw the swirling water rising toward their feet.

"Pull!" screamed Nancy, pounding on the door as hard as she could. "Turn the handle and pull the bench!"

An eternity seemed to pa.s.s as the water lapped closer. Then slowly the door began to open inward. Gas fumes poured out, but Nancy staggered forward, holding her breath. Behind her came Amos Hendrick. Grumper, paralyzed with fear, cowered on the steps below.

Nancy caught a glimpse of their rescuer, a young man in a gas mask which protected him from the fumes. He was Ned!

"Water coming!" she gasped. "Man still below!"

"Go on!" he shouted to Nancy.

She a.s.sisted Amos Hendrick to the pa.s.sageway, where the air was comparatively fresh. Ned ran down to the frightened little man on the stairway and hustled him inside the laboratory. Barely in time to prevent the room from being flooded, Ned pushed the bench door shut.

Then he turned to Grumper. The man had collapsed on the floor, a victim of the fumes he had concocted!

Ned picked him up in a fireman's carry. When he staggered into the cottage with his burden, he pulled off his gas mask. Nancy's first question was:

"Where's George?"

"She went down to the outside cave entrance with a trooper," Ned replied. "Nancy, you owe your life to George," he said soberly.

"And to you!" Nancy said.