“there’s one thing, which we have got to realize at once,” said antony, “and that is that if we don’t find it easily, we shan’t find it at all.”

“you mean that we shan’t have time?”

“neither time nor opportunity. which is rather a consoling thought to a lazy person like me.”

“but it makes it much harder, if we can’t really look properly.”

“harder to find, yes, but so much easier to look. for instance, the passage might begin in cayley’s bedroom. well, now we know that it doesn’t.”

“we don’t know anything of the sort,” protested bill.

“we know for the purposes of our search. obviously we can’t go tailing into cayley’s bedroom and tapping his wardrobes; and obviously, therefore, if we are going to look for it at all, we must assume that it doesn’t begin there.”

“oh, i see.” bill chewed a piece of grass thoughtfully. “anyhow, it wouldn’t begin on an upstairs floor, would it?”

“probably not. well, we’re getting on.”

“you can wash out the kitchen and all that part of the house,” said bill, after more thought. “we can’t go there.”

“right. and the cellars, if there are any.”

“well, that doesn’t leave us much.”

“no. of course it’s only a hundred-to-one chance that we find it, but what we want to consider is which is the most likely place of the few places in which we can look safely.”

“all it amounts to,” said bill, “is the living-rooms downstairs—dining-room, library, hall, billiard-room and the office rooms.”

“yes, that’s all.”

“well, the office is the most likely, isn’t it?”

“yes. except for one thing.”

“what’s that?”

“well, it’s on the wrong side of the house. one would expect the passage to start from the nearest place to which it is going. why make it longer by going under the house first?”

“yes, that’s true. well, then, you think the dining-room or the library?”

“yes. and the library for choice. i mean for our choice. there are always servants going into dining-rooms. we shouldn’t have much of a chance of exploring properly in there. besides, there’s another thing to remember. mark has kept this a secret for a year. could he have kept it a secret in the dining-room? could miss norris have got into the dining-room and used the secret door just after dinner without being seen? it would have been much too risky.”

bill got up eagerly.

“come along,” he said, “let’s try the library. if cayley comes in, we can always pretend we’re choosing a book.”

antony got up slowly, took his arm and walked back to the house with him.

the library was worth going into, passages or no passages. antony could never resist another person’s bookshelves. as soon as he went into the room, he found himself wandering round it to see what books the owner read, or (more likely) did not read, but kept for the air which they lent to the house. mark had prided himself on his library. it was a mixed collection of books. books which he had inherited both from his father and from his patron; books which he had bought because he was interested in them or, if not in them, in the authors to whom he wished to lend his patronage; books which he had ordered in beautifully bound editions, partly because they looked well on his shelves, lending a noble colour to his rooms, partly because no man of culture should ever be without them; old editions, new editions, expensive books, cheap books—a library in which everybody, whatever his taste, could be sure of finding something to suit him.

“and which is your particular fancy, bill?” said antony, looking from one shelf to another. “or are you always playing billiards?”

“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 re-arrangement 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.

“we shall have to take every blessed book down,” he said, “before we can be certain that we haven’t missed it.”

“anyway,” said antony, “if we take them down one at a time, nobody can suspect us of sinister designs. after all, what does one go into a library for, except to take books down?”

“but there’s such a frightful lot.”

antony’s pipe was now going satisfactorily, and he got up and walked leisurely to the end of the wall opposite the door.

“well, let’s have a look,” he said, “and see if they are so very frightful. hallo, here’s your ‘badminton.’ you often read that, you say?”

“if i read anything.”

“yes.” he looked down and up the shelf. “sport and travel chiefly. i like books of travel, don’t you?”

“they’re pretty dull as a rule.”

“well, anyhow, some people like them very much,” said antony, reproachfully. he moved on to the next row of shelves. “the drama. the restoration dramatists. you can have most of them. still, as you well remark, many people seem to love them. shaw, wilde, robertson—i like reading plays, bill. there are not many people who do, but those who do are usually very keen. let us pass on.”

“i say, we haven’t too much time,” said bill restlessly.

“we haven’t. that’s why we aren’t wasting any. poetry. who reads poetry nowadays? bill, when did you last read ‘paradise lost’?”

“never.”

“i thought not. and when did miss calladine last read ‘the excursion’ aloud to you?”

“as a matter of fact, betty—miss calladine—happens to be jolly keen on—what’s the beggar’s name?”

“never mind his name. you have said quite enough. we pass on.”

he moved on to the next shelf.

“biography. oh, lots of it. i love biographies. are you a member of the johnson club? i bet mark is. ‘memories of many courts’—i’m sure mrs. calladine reads that. anyway, biographies are just as interesting as most novels, so why linger? we pass on.” he went to the next shelf, and then gave a sudden whistle. “hallo, hallo!”

“what’s the matter?” said bill rather peevishly.

“stand back there. keep the crowd back, bill. we are getting amongst it. sermons, as i live. sermons. was mark’s father a clergyman, or does mark take to them naturally?”

“his father was a parson, i believe. oh, yes, i know he was.”

“ah, then these are father’s books. ‘half-hours with the infinite’—i must order that from the library when i get back. ‘the lost sheep,’ ‘jones on the trinity,’ ‘the epistles of st. paul explained.’ oh, bill, we’re amongst it. ‘the narrow way, being sermons by the rev. theodore ussher’—hal-lo!”

“what is the matter?”

“william, i am inspired. stand by.” he took down the reverend theodore ussher’s classic work, looked at it with a happy smile for a moment, and then gave it to bill.

“here, hold ussher for a bit.”

bill took the book obediently.

“no, give it me back. just go out into the hall, and see if you can hear cayley anywhere. say ‘hallo’ loudly, if you do.”

bill went out quickly, listened, and came back.

“it’s all right.”

“good.” he took the book out of its shelf again. “now then, you can hold ussher. hold him in the left hand—so. with the right or dexter hand, grasp this shelf firmly—so. now, when i say ‘pull,’ pull gradually. got that?”

bill nodded, his face alight with excitement.

“good.” antony put his hand into the space left by the stout ussher, and fingered the back of the shelf. “pull,” he said.

bill pulled.

“now just go on pulling like that. i shall get it directly. not hard, you know, but just keeping up the strain.”

his fingers went at it again busily.

and then suddenly the whole row of shelves, from top to bottom, swung gently open towards them.

“good lord!” said bill, letting go of the shelf in his amazement.

antony pushed the shelves back, extracted ussher from bill’s fingers, replaced him, and then, taking bill by the arm, led him to the sofa and deposited him in it. standing in front of him, he bowed gravely.

“child’s play, watson,” he said; “child’s play.”

“how on earth—”

antony laughed happily and sat down on the sofa beside him.

“you don’t really want it explained,” he said, smacking him on the knee; “you’re just being watsonish. it’s very nice of you, of course, and i appreciate it.”

“no, but really, tony.”

“oh, my dear bill!” he smoked silently for a little, and then went on, “it’s what i was saying just now—a secret is a secret until you have discovered it, and as soon as you have discovered it, you wonder why everybody else isn’t discovering it, and how it could ever have been a secret at all. this passage has been here for years, with an opening at one end into the library, and at the other end into the shed. then mark discovered it, and immediately he felt that everybody else must discover it. so he made the shed end more difficult by putting the croquet-box there, and this end more difficult by—” he stopped and looked at the other “by what, bill?”

but bill was being watsonish.

“what?”

“obviously by re-arranging his books. he happened to take out ‘the life of nelson’ or ‘three men in a boat,’ or whatever it was, and by the merest chance discovered the secret. naturally he felt that everybody else would be taking down ‘the life of nelson’ or ‘three men in a boat.’ naturally he felt that the secret would be safer if nobody ever interfered with that shelf at all. when you said that the books had been re-arranged a year ago—just about the time the croquet-box came into existence—of course, i guessed why. so i looked about for the dullest books i could find, the books nobody ever read. obviously the collection of sermon-books of a mid-victorian clergyman was the shelf we wanted.”

“yes, i see. but why were you so certain of the particular place?”

“well, he had to mark the particular place by some book. i thought that the joke of putting ‘the narrow way’ just over the entrance to the passage might appeal to him. apparently it did.”

bill nodded to himself thoughtfully several times. “yes, that’s very neat,” he said. “you’re a clever devil, tony.”

tony laughed.

“you encourage me to think so, which is bad for me, but very delightful.”

“well, come on, then,” said bill, and he got up, and held out a hand.

“come on where?”

“to explore the passage, of course.”

antony shook his head.

“why ever not?”

“well, what do you expect to find there?”

“i don’t know. but you seemed to think that we might find something that would help.”

“suppose we find mark?” said antony quietly.

“i say, do you really think he’s there?”

“suppose he is?”

“well, then, there we are.”

antony walked over to the fireplace, knocked out the ashes of his pipe, and turned back to bill. he looked at him gravely without speaking.

“what are you going to say to him?” he said at last.

“how do you mean?”

“are you going to arrest him, or help him to escape?”

“i—i—well, of course, i—” began bill, stammering, and then ended lamely, “well, i don’t know.”

“exactly. we’ve got to make up our minds, haven’t we?”

bill didn’t answer. very much disturbed in his mind, he walked restlessly about the room, frowning to himself, stopping now and then at the newly discovered door and looking at it as if he were trying to learn what lay behind it. which side was he on, if it came to choosing sides—mark’s or the law’s?

“you know, you can’t just say, ‘oh—er—hallo!’ to him,” said antony, breaking rather appropriately into his thoughts.

bill looked up at him with a start.

“nor,” went on antony, “can you say, ‘this is my friend mr. gillingham, who is staying with you. we were just going to have a game of bowls.’”

“yes, it’s dashed difficult. i don’t know what to say. i’ve been rather forgetting about mark.” he wandered over to the window and looked out on to the lawns. there was a gardener clipping the grass edges. no reason why the lawn should be untidy just because the master of the house had disappeared. it was going to be a hot day again. dash it, of course he had forgotten mark. how could he think of him as an escaped murderer, a fugitive from justice, when everything was going on just as it did yesterday, and the sun was shining just as it did when they all drove off to their golf, only twenty-four hours ago? how could he help feeling that this was not real tragedy, but merely a jolly kind of detective game that he and antony were playing?

he turned back to his friend.

“all the same,” he said, “you wanted to find the passage, and now you’ve found it. aren’t you going into it at all?”

antony took his arm.

“let’s go outside again,” he said. “we can’t go into it now, anyhow. it’s too risky, with cayley about. bill, i feel like you—just a little bit frightened. but what i’m frightened of i don’t quite know. anyway, you want to go on with it, don’t you?”

“yes,” said bill firmly. “we must.”

“then we’ll explore the passage this afternoon, if we get the chance. and if we don’t get the chance, then we’ll try it to-night.”

they walked across the hall and out into the sunlight again.

“do you really think we might find mark hiding there?” asked bill.

“it’s possible,” said antony. “either mark or—” he pulled himself up quickly. “no,” he murmured to himself, “i won’t let myself think that—not yet, anyway. it’s too horrible.”