Travers, the Third Form boy, rushed off to impart his information to other hearers, and the three chums passed on through the archway, and came to a stand-still in a quiet corner of the paved playground.
"Well," asked Diggory, "who did it ?" "Who d'you think it was ?" retorted Jack Vance.
"Why, some of Thurston's lot, I believe." "So do I." Mugford, who was always rather slow at grasping a new idea, opened his eyes in astonishment.

"But," he exclaimed, "how about the paper and the screw-driver ?" "Pooh!" answered Diggory, "how about that cipher note that said, 'To-night' ?" "Of course," added Jack Vance, "they'd evidently arranged it beforehand, and that paper was to say when they were to do the trick." It seems possible sometimes to come by wrong roads to a right conclusion; and though the boys were mistaken in changing from their first opinion as to the meaning of the note, yet in this instance their error caused them to hit the right nail on the head.
"It was one of Thurston's lot who did it," repeated Diggory decisively; "neither Oaks nor Allingford would ever dream of doing such a mad thing." "I don't see exactly how you can prove it," said Jack Vance thoughtfully; "that one word 'To-night' might mean anything." "Of course it's no proof in itself," answered the other; "but what I mean to say is, that if the doctor, or any other sensible chap, knew all we do about the cipher, and what they said at their last meeting, he wouldn't doubt for a moment but that it was one of them who screwed up Grice's door.

Travers says the doctor has sent for Oaks and old Ally; it'll be an awful shame if they get into a row." "I don't see how they are going to get out of it," sighed Mugford.
"Then I do," answered Diggory stoutly, with a sudden flash in his bright eyes: "the Triple Alliance can get them out!" "How ?" "Why, we must tell all we know, and show Dr.Denson the note." "When ?" "Now." "Won't it be sneaking ?" "I should consider we were beastly sneaks if we didn't." "So we should be!" exclaimed Jack Vance.

"They've always been jolly decent to us, and it was on our account they had this row with Grice." "If Noaks finds we've split, he'll send that knife to the police," said Mugford.
"I don't care a straw what Noaks does," answered Diggory boldly.
"You fellows needn't have anything to do with it; I'll go and tell Dr.
Denson myself." "No; I'll come too," said Jack.
"So'll I," added Mugford; and off they started.

It was always a great ordeal to enter the doctor's study, even in what might be termed times of peace; and now, as Diggory turned the handle of the door, in answer to the muffled "Come in" which had followed his knock, the three friends experienced a sudden shortness of breath, and an unpleasant sinking sensation at the pit of the stomach.
The two prefects were standing at the front of the writing-table.
Allingford's face was very white, and Oaks's very red, "for all the world like the Wars of the Roses," as Jack Vance afterwards remarked, though it would be difficult to clearly understand the simile.
The head-master glanced round for a moment to see who had entered the room, and, without taking any further notice of the three juveniles, continued the speech he was in the act of making when they entered the apartment.
"I am not going to defend the action of Mr.Grice," he was saying.
"We are all apt to make mistakes, and I will tell you candidly that on this occasion I think Mr.Grice was unwise; but it is absolutely necessary that I should uphold the authority of my masters.