The door of the house would not open for them. Bruce threatened to burst it in with his shoulders, but Bart advised him not to do so, unless as a last resort.

Then a window was found that would open, and soon they had clambered in.

There was some furniture in the house, but still the place had the same dreary, deserted air of the big building they had just left.

Browning began by shouting Frank's name, to which cry there was no answer. The rising wind rattled a loose window.

It did not take them long to go through the house, to which there was no cellar, and they found nothing to indicate that a human being had entered the place for months.

As they stood outside, after getting out of the window and closing it behind them, they looked at each other in a helpless manner.

"What has become of him?" asked Bart, huskily.

"That is what I would like to know," confessed Bruce. "He seems to have disappeared completely."

"And the man in gray——"

"Is gone, too."

"Browning, I am afraid Merry was lured into some sort of a trap."

"So am I."

"Why should they take him in particular, and not harm any of the rest of us?"

"Perhaps their motto is one at a time."

"No. I believe Frank was selected out of our party as the one to get out of the way. He was determined to solve the mystery of this wretched island, and he was the leader of our party. The ruffians fancied that they would put an end to all trouble by getting him out of the way, for they fancied we would run at once."

Browning grunted, and Hodge went on swiftly and fiercely:

"By the eternal skies, they made a big mistake! I'll not leave this island till I know what has happened to Frank Merriwell, or I am dead!"

"Nor I," nodded Bruce. "I'm with you, old man."

"If he has been harmed," Bart went on, "the wretches who did the dirty work shall suffer! I swear it!"

"I'm another."

"We will bring them to justice!"

"Or kick the bucket trying."

They shook hands on it, and they were in deadly earnest.

They decided not to return to the yacht by the path, but to go over the island and through the woods. Thus, by chance, they followed almost directly in Frank's footsteps.

As they drew near to the dark woods, Browning felt a tightening at his heart—a sensation similar to that he had once before experienced as he stood beside the lonely grave in the dark glade. He sought to throw it off, but could not do so.

"Come," he said.

"Which way?" asked Bart.

"This way."

He seemed to feel something drawing him toward the grave in the glade, and Bart followed without another word.

Unconsciously the big Yale man stepped softly, as if he feared to alarm somebody or something. The moss beneath his feet gave no sound. Not even a twig snapped. Without knowing that he did so, Hodge imitated Browning's stealthy manner.

The wind soughed through the pines and cedars in a fitful manner. There seemed to be strange rustlings in the air.

At the edge of the glade Bruce halted. There was the grave, with the gray headstone. He stood there staring at it. Somehow he was possessed by a feeling that the grave had something to do with the vanishing of Frank Merriwell, although his reason told him that such a thing was folly.

"What is the matter?"

Hodge almost whispered the question, for he was beginning to feel the uncanny air that overshadowed the place.

"There is the grave," said Bruce.

"What grave?"

"Why, the one we told you about—the grave of the Boston man who disappeared in such a mysterious manner. It is supposed that he was murdered on this island and buried there."

Bart shivered.

"You act as if you half expected to see another grave beside that one," he muttered.

"Not so soon."

"But to-morrow——"

"If Frank has been foully dealt with, the villains have not been given time to make another grave. His body is hidden somewhere. But I will not believe anything of the kind has happened. We shall find him somewhere—alive and well."

"We must!"

Bruce remembered the strange whispering they had heard there when he and Frank visited the place, and now he listened, half expecting to hear it again.

The silence was unbroken save by the mournful sound of the wind in the trees.

Bruce went forward quickly and stood by the grave. Bart came up, and together they looked down at the gray headstone.

"What is that?" asked Hodge, pointing. "Somebody has been doing something to the stone since it was placed here."

They bent down and looked at the stone.

"Why," cried Bruce, "the first name has been chiseled off! Another name has been put on! That name is——"

"Frank Merriwell!"

Astounded, they stared at the headstone. What did it mean? Why was that name upon it?

The tightening sensation grew around Browning's heart. All at once it seemed that the mystery of the island was deeper and darker than ever before.

"Now what do you think of that?" cried Bart, huskily.

Bruce shook his head, for the moment feeling that he was not able to speak. It did not seem that he could govern his voice. All sorts of wild fancies were rushing through his head.

He looked at the mound, and a feeling of relief came to him when he saw that it seemed undisturbed.

Hodge was shaking. He reached out and grasped the big fellow's arm with a savage clutch.

"Was it—was it meant for a warning?" he asked.

"Yes," said Bruce, quickly grasping at that explanation, "it must have been. You have struck it, Hodge."

"Then it is not likely Frank saw it."

"Perhaps not, and yet he may have come here."

Then they stood there a long time, silently staring at that stone, on which was chiseled the name of the friend they held dearest in all the world.

At last Bruce hoarsely said:

"Come, let's get away from here!"

"But it may be that—somehow—we may strike a clew here. This may be a clew. This may explain what has happened."

"If this explains it, there is but one construction to be placed on Frank's remarkable disappearance."

"And that is that he is——"

"Dead!"

In the treetops the wind seemed to repeat the word in a whisper.

But neither Bart nor Bruce were willing to believe that Frank Merriwell was dead, for all that his name was there before them on the gray stone at the head of the lonely grave.

"Dead or living, I'll never rest till I know the truth!" came passionately from Bart's lips. "If he is dead, the murderers shall suffer!"

"We must throw off the feeling that anything so awful has happened. Even now he may be with the others at the yacht. While we have been searching for him, he may have returned."

Hodge caught at this eagerly.

"You are right!" he said. "Come on; we will hurry back there."

They left the glade, turning to look back as they passed on into the gloomy woods. They were glad to get away.

At first they hurried on, their hearts buoyant with the thought that they should find him waiting for them at the yacht. He would laugh at them, would jolly them because of their foolish fears. The placing of his name on the headstone of the grave was a ghastly joke, and nothing more.

In his mind Browning was thinking how he would growl at Merry for causing them so much trouble. He even thought of the words he would use.

But as they came nearer and nearer to the side of the island near which the yacht was anchored, their spirits fell again and they were beset by doubts and fears. What if they should not find Frank waiting for them when they arrived?

These doubts caused them to walk slower and slower, for they dreaded to hear that Frank was still missing.

"It seems to me," said Bart, "that it is very probable Merriwell will not be with Jack and Hans."

"He may not be," confessed Bruce.

"If he had returned, they would have fired guns and done things to let us know it."

"We might not have heard them."

"We should. The wind is right. We are near the yacht now."

Bruce felt like turning back and making another search. He dreaded to return and report that they had discovered nothing save the name of the missing lad on the headstone of a grave.

All at once they came out of the woods upon the high bank, from which position they could look down into the cove where the yacht lay. There she was, swinging idly with the incoming tide, and on her deck they could see Dunnerwust and Diamond. Merriwell was not in sight.

Almost as soon as they came out of the thick woods, they were seen by Diamond, and he called to them:

"What have you found?"

"Nothing," answered Hodge, gloomily. "Hasn't Frank returned?"

"No!"