“Brilliant deductive reasoning.  Well, then you suddenly saw her?”

“Yes, she walked across that side of the lawn.”  He indicated the opposite side, nearer to the house.

“She couldn’t have been hiding in the ditch?  Do you call it the moat, by the way?”

“Mark does.  We don’t among ourselves.  No, she couldn’t.  Betty and I were here before the others, and walked round a bit.  We should have seen her.”

“Then she must have been hiding in the shed.  Or do you call it the summer-house?”

“We had to go there for the bowls, of course.  She couldn’t have been there.”

“Oh!”

“It’s dashed funny,” said Bill, after an interval for thought.  “But it doesn’t matter, does it?  It has nothing to do with Robert.”

“Hasn’t it?”

“I say, has it?” said Bill, getting excited again.

“I don’t know.  We don’t know what has, or what hasn’t.  But it has got something to do with Miss Norris.  And Miss Norris—­” He broke off suddenly.

“What about her?”

“Well, you’re all in it in a kind of way.  And if something unaccountable happens to one of you a day or two before something unaccountable happens to the whole house, one is well, interested.”  It was a good enough reason, but it wasn’t the reason he had been on the point of giving.

“I see.  Well?”

Antony knocked out his pipe and got up slowly.

“Well then, let’s find the way from the house by which Miss Norris came.”

Bill jumped up eagerly.

“By Jove!  Do you mean there’s a secret passage?”

“A secluded passage, anyway.  There must be.”

“I say, what fun!  I love secret passages.  Good Lord, and this afternoon I was playing golf just like an ordinary merchant!  What a life!  Secret passages!”

They made their way down into the ditch.  If an opening was to be found which led to the house, it would probably be on the house side of the green, and on the outside of the ditch.  The most obvious place at which to begin the search was the shed where the bowls were kept.  It was a tidy place as anything in Mark’s establishment would be.  There were two boxes of croquet things, one of them with the lid open, as if the balls and mallets and, hoops (neatly enough put away, though) had been recently used; a box of bowls, a small lawn-mower, a roller and so forth.  A seat ran along the back of it, whereon the bowls-players could sit when it rained.

Antony tapped the wall at the back.

“This is where the passage ought to begin.  It doesn’t sound very hollow, does it?”

“It needn’t begin here at all, need it?” said Bill, walking round with bent head, and tapping the other walls.  He was just too tall to stand upright in the shed.

“There’s only one reason why it should, and that is that it would save us the trouble of looking anywhere else for it.  Surely Mark didn’t let you play croquet on his bowling-green?” He pointed to the croquet things.