As soon as Paul had accomplished his purpose, and seen the flag waving in its old place on the turret, he went to the room of Mr. Weevil. He knew well enough that inquiries would be made respecting the return of the flag, and therefore he took the straightforward course of going at once to headquarters.

"Come in!" came the voice of the master in response to the knock on his door.

He was pacing to and fro the room—the same room in which Paul had seen him on that never-to-be-forgotten night with Zuker. He stopped as Paul entered, and regarded him in his usual manner—through half-closed eyes.

"You, Percival! What is it you want with me?" came the sharp answer.

"I only came to tell you that the flag is back in its old place, sir."

"I know—I know! And you brought it back, I understand? I meant inquiring into the matter. I'm glad you've forestalled me. You want to explain—eh? That's what you've come for—eh?"

"That's what I've come for, sir," answered Paul, astonished that he should have gained such speedy information as to what had happened. Sometimes, indeed, it seemed as though those half-closed eyes not only saw further than other eyes, but that they had the faculty of double sight as well.

"And yet I don't know whether I can call it an explanation, for there are things which cannot be explained."

"Not explained? How do you mean, sir?" came the sharp answer.

"I received the flag back from a friend of mine—a proved friend—on the solemn promise that I would not make use of the information he had given me to get any of the fellows who had taken it into a scrape."

"Why did you make that promise?"

"Because it was the only way of getting the flag back."

"And that is all the information you can give me?"

"That is all, sir."

"And you call it an explanation? Really, sir, it is one of the most extraordinary I have ever heard! And you expect me to accept it?" demanded the master, facing Paul, and looking him fully in the eyes.

"I trust so, sir, because I can give no other—have no other to give."

Mr. Weevil did not at once answer, but took two or three more turns across the room.

"I believe you to be a lad of honour, Percival," he said, stopping once more, "and a lad of sense. Let me put it to you, then, as a lad of honour and of sense. Supposing I am perfectly ready to accept your statement, do you really believe that the school will be as ready to accept it?"

"The school might be curious to know more, sir, but if you accept my explanation as sufficient, I don't see why anybody should question it."

"Yes, yes; that might be well enough. But there have been one or two rather mysterious things that have happened within the last month or two which have never been cleared up. There was the breaking open of my desk, for instance, and the torn pages in the Black Book."

"I could mention a still greater mystery that wants clearing up," thought Paul, as his mind went back to the afternoon when he had seen the master enter the strange hiding-place of Zuker.

"The culprit in that case has never been found out. It still remains a mystery," continued Mr. Weevil. "Then came the mysterious disappearance of the flag, and its equally mysterious return. The school will be getting suspicious—uneasy. If no better explanation is forthcoming than that you have given me, suspicion will grow—I am certain of it."

Paul saw that the master was right. Still, he had no intention of giving up his secret.

"I have given my word, sir," he answered firmly. "You would not have me break it?"

"You said that you have received the flag from a friend, if my memory serves me—a proved friend?"

"Yes, sir."

"May I ask in what way his friendship has been proved?"

How could Paul answer him? How could he tell the man before him in what way Wyndham had proved his friendship to him? Suddenly, it flashed into Paul's mind that the bold course was the best.

"When I was home last vacation, sir, a gentleman had an accident with his horse. He asked me to take a packet for him to Mr. Moncrief, the father of Moncrief minor. I took the packet. On the way I was set on by two ruffians. I got away from them, but they followed me, and would have got the packet from me had it not been for the friend I speak of."

Mr. Weevil's eyes began closing as Paul was speaking. When he finished they opened again.

"What did this friend do?"

"Hid me till the ruffians had gone."

"Good! And that enabled you to get the packet to Mr. Moncrief?"

"Yes, sir."

"Excellent! But, do you know, Percival, this really seems a stranger story than the other."

"Perhaps so, sir; but I can prove every word of it, if you like. By your permission, I will send for Mr. Moncrief——"

"No, no; that is altogether unnecessary!" said the master quickly. "Strange though the story is, I accept every word of it—every word. The friend you speak of was indeed a friend in need. You must keep your word to him—it would be an act of baseness to break it. I did not know the facts, you see. You may leave the rest to me."

Paul's heart bounded joyfully. The bold course had been the right one. It had succeeded where a weaker course might have utterly failed.

"Thank you, sir. It is very kind of you."

Paul was about to withdraw, when the master called him back.

"Let me see, there was a letter came for you while you were out. There it is in the rack."

Paul took the letter from the rack as Mr. Weevil turned to his books. Again his heart gave a great bound. One glance at it told him who it was from. It was the letter he had been so anxiously awaiting from Mr. Walter Moncrief.

"It is for you, isn't it?" Mr. Weevil asked, glancing into the boy's eager face.

"Yes, sir," answered Paul, wondering whether the master suspected who it was from or had any knowledge of its contents. He inspected the envelope as he hastened to his dormitory. No; it did not seem to have been tampered with. Mr. Weevil could not have seen its contents. On reaching his room, he tore open the envelope, and read:

"My dear Paul,—I received your first letter, but was away from home at the time, so was unable to answer it. Pardon my delay. You need not worry about the man Zuker. I am kept informed as to his movements.

"With regard to your master Mr. Weevil, I quite agree with you—I cannot think that he has anything to do with a traitor to his country, though appearances may be against him. At any rate, till anything is distinctly proved, give him the respect due to a scholar and a gentleman.

"To turn to other and more agreeable matters. I trust that Harry is getting on well. He seems too busy to write much. And when he does write, it's nothing but 'Plunger, Plunger, Plunger,' from start to finish. You would fancy there was nobody else but Plunger in existence. Tell him that when he can get away from Plunger we shall be very glad to hear from him again.

"I know the great friendship there is between you and my nephew Stanley. I only hope that Harry will find as good and worthy a friend. Tell Stanley that he has to come here during next vacation, and bring you with him. I think we shall be able to provide you with plenty of amusement, though I can't promise you it will be of so exciting a kind as you had last vacation.—Your sincere friend,

"Walter Moncrief."