“What’ll we do?” whispered Moriarty. It was at last safe to whisper.

“Wait,” said O’Hara, “I’m thinking.”

O’Hara thought. For many minutes he thought in vain. At last there came flooding back into his mind a memory of the days of his faghood. It was after that that he had been groping all the time. He remembered now. Once in those days there had been an unexpected function in the middle of term. There were needed for that function certain chairs. He could recall even now his furious disgust when he and a select body of fellow fags had been pounced upon by their form-master, and coerced into forming a line from the junior block to the cloisters, for the purpose of handing chairs. True, his form-master had stood ginger-beer after the event, with princely liberality, but the labour was of the sort that gallons of ginger-beer will not make pleasant. But he ceased to regret the episode now. He had been at the extreme end of the chair-handling chain. He had stood in a passage in the junior block, just by the door that led to the masters’ garden, and which—­he remembered—­was never locked till late at night. And while he stood there, a pair of hands—­apparently without a body—­had heaved up chair after chair through a black opening in the floor. In other words, a trap-door connected with the vault in which he now was.

He imparted these reminiscences of childhood to Moriarty. They set off to search for the missing door, and, after wanderings and barkings of shins too painful to relate, they found it. Moriarty lit a match. The light fell on the trap-door, and their last doubts were at an end. The thing opened inwards. The bolt was on their side, not in the passage above them. To shoot the bolt took them one second, to climb into the passage one minute. They stood at the side of the opening, and dusted their clothes.

“Bedad!” said Moriarty, suddenly.

“What?”

“Why, how are we to shut it?”

This was a problem that wanted some solving. Eventually they managed it, O’Hara leaning over and fishing for it, while Moriarty held his legs.

As luck would have it—­and luck had stood by them well all through—­there was a bolt on top of the trap-door, as well as beneath it.

“Supposing that had been shot!” said O’Hara, as they fastened the door in its place.