“I have a look at Badminton sometimes,” said Bill. “It’s over in that corner there.” He waved a hand.

“Over here?” said Antony, going to it.

“Yes.” He corrected himself suddenly. “Oh, no, it’s not. It’s over there on the right now. Mark had a grand rearrangement of his library about a year ago. It took him more than a week, he told us. He’s got such a frightful lot, hasn’t he?”

“Now that’s very interesting,” said Antony, and he sat down and filled his pipe again.

There was indeed a “frightful lot” of books. The four walls of the library were plastered with them from floor to ceiling, save only where the door and the two windows insisted on living their own life, even though an illiterate one. To Bill it seemed the most hopeless room of any in which to look for a secret opening.