Frank was determined to solve the mystery of the unknown man. He did not tell Rattleton everything concerning his adventure of the previous night, although he was forced to explain that he had been in an encounter, and that he did not know who his assailants were.

The theatre party had wondered greatly at Frank's sudden disappearance, and Frank confessed that he had followed the mysterious unknown, who had given him the slip.

"That fellow is playing the shadow on you, Frank," cried Harry, indignantly. "He's up to some sort of crookedness."

"He must bear a charmed life, or he would have been killed the night he jumped from the New London special," said Frank.

"He decided it was best to take chances by jumping rather than to fall into the hands of Old Eli's sons, and I think he was right."

Creighton came around to inquire how it happened that Merriwell disappeared so suddenly the previous evening.

Since the boat race Creighton had sought Merriwell's company, although he had scarcely given Frank any attention before that.

Creighton was a prominent society man and had considerable influence at Yale; his friendship was of value to any fellow on whom he saw fit to bestow it.

His father was rich, and Charlie spent money freely, as his whims dictated. Not even those with whom he was not on friendly terms, however, could justly accuse him of being a cad.

"Awfully jolly time last night," yawned Creighton. "It was rather kiddish, but it is a relief to play the boy once in a while. It capped the whole business when the actors themselves finished the fun by giving the manager away in the last act."

Frank smiled, but did not explain his connection with the crowning event of the evening.

"Jove! I'm hungry," Charlie declared. "Come on, Merriwell and Rattleton, we'll go down to Bob's, and have a chop."

He would not take no for an answer, and so, a few minutes later, the trio crossed the campus, Creighton in the middle, his arms locked with those of the other lads. All were laughing and joking in a light-hearted manner.

Creighton took them directly to a restaurant that was famous for its chops. They ordered, Charlie and Harry taking ale with their food.

Just as the chops were brought on, a man came in and took a seat at a table nearby. This man was dressed in a new suit of "store clothes," and wore a full beard. He gave his order to the waiter in a low tone, and then began perusing a paper, behind which his face was almost entirely hidden.

Rattleton happened to sit so that he naturally looked toward the man, and, several times, he caught that individual peering over the top of the paper. It did not take Harry long to note that the person with the paper seemed to be watching Frank Merriwell.

Suddenly Frank's roommate arose, and, with two swift steps, he was at the man's side. Without a word, Harry caught the gentleman by the beard, which he gave a sharp jerk.

The beard came off in Harry's hand!

It was false!

"Look, Frank!" cried Rattleton, pointing at the smooth-shaven face exposed; "it is the mysterious man who has been following you about!"

It was in truth the mysterious unknown, and Frank was on his feet in a twinkling, resolved not to let the man escape till he had given a full explanation of his remarkable conduct.

To Merriwell's surprise, the stranger showed no desire to run away, but sat smiling serenely up at him, calmly observing:

"Do not excite yourself, Mr. Merriwell; there is no reason for it. I have completed my business in a most satisfactory manner, and I am now ready to explain everything to you."

"It is an explanation which I expect and demand," said Frank, coldly. "It is no more than fair that I should have one, as you have shown yourself my persistent enemy, and that without any just cause that I know of."

"You are mistaken," returned the man; "instead of your enemy, I have been your firm friend from the very first."

"I fail to see how you can make that out."

"I will call at your rooms this evening and give you a full explanation."

"No!" cried Frank, promptly, "you will give me an explanation here and immediately."

"I do not think you will press me to that," was the calm assertion. "I might speak of affairs of a personal and family nature."

"You—you speak of such affairs—to me? Now it strikes me that you are attempting a bluff, sir; but it will not work."

The stranger reached into his pocket and took out something, which he held up before Frank's eyes.

"This," he said, with confidence, "will convince you that I speak nothing but the truth."

"My father's ring!" gasped Frank.

"Yes," bowed the man; "it is the ring that led him to one of the richest mines in the Southwest. He said that it would simply be necessary for me to show it to you, and you would know that he sent me. Shall I call this evening, Mr. Merriwell?"

"If you please, sir," said Frank, bowing respectfully.

The boys were surprised, but Frank said he would explain some time later.

That evening the stranger called, as he had said he would. Frank had taken pains to run Harry out of the room, so they were quite alone. The boy locked the door, as a precaution against unwelcome interruptions.

The mysterious man introduced himself as David Scott, the confidential agent of Charles Merriwell, Frank's unfortunate father, who had spent the best years of his life and separated himself from his family and friends in the mad search after "phantom fortune."

At last Charles Merriwell had "struck it rich," and he was now a very wealthy man; but he was broken in health, and he often feared for his reason. As Charles Merriwell had been eccentric and unfathomable all his life while poor, thus he remained now that he was rich. Of late he had been seized by a conviction that he could not live long, and it was his desire to make a will that would give almost his entire wealth to his son. But before he made such a will, Mr. Merriwell decided to know just what sort of a young man his son had become. As he did not feel like leaving his mine and going East to investigate, he sent his confidential clerk, David Scott.

In his instructions to Scott, Charles Merriwell showed the peculiarities of his character. He provided the agent with plenty of money, and instructed him to thoroughly probe the inward character of the youth about which he was to acquire information. Scott was instructed to discover all of Frank's bad habits, and to determine if the lad could be led astray by evil influence, or in any other manner. The agent had carried out his instructions to his complete satisfaction, and he complimented the blushing boy on his integrity of character and sterling manhood.

Scott explained how he had pretended to ally himself with Frank's foes, and thus had heard the plots against the boy. He had sent Frank the warnings, and he had secured the aid of Plug Kirby to aid him in beating off Merriwell's ruffianly assailants.

"I scarcely think you will be troubled any more by your enemies," declared Scott. "I had a session with them last night, after the failure of their attempt on you, and I sent the varmints scurrying for tall timber in a hurry. I told them that I was your friend, and not your enemy, and that I would come up as a witness against them if you saw fit to prosecute them. Then they begged me to keep still, and agreed to let up on you for good and all if I wouldn't chirp. I made the galoots no promises."

For hours Frank and Scott sat and talked of Charles Merriwell, his health, his mine and his plans. And when the man departed, it was with a letter from Frank Merriwell to Charles Merriwell in his possession.

The next evening Frank received a call which surprised him greatly. What it was the next chapter will tell.