“Oh—somebody shooting at a dog,” said the man negligently.

“At a dog!” said Aaron, with round eyes.

He finished his tea, and went out into the town. His hotel was not far from the cathedral square. Passing through the arcade, he came in sight of the famous cathedral with its numerous spines pricking into the afternoon air. He was not as impressed as he should have been. And yet there was something in the northern city—this big square with all the trams threading through, the little yellow Continental trams: and the spiny bulk of the great cathedral, like a grey–purple sea– urchin with many spines, on the one side, the ornamental grass–plots and flower beds on the other: the big shops going all along the further strands, all round: and the endless restless nervous drift of a north Italian crowd, so nervous, so twitchy; nervous and twitchy as the slipping past of the little yellow tram–cars; it all affected him with a sense of strangeness, nervousness, and approaching winter. It struck him the people were afraid of themselves: afraid of their own souls, and that which was in their own souls.

Turning up the broad steps of the cathedral, he entered the famous building. The sky had cleared, and the freshened light shone coloured in living tablets round the wonderful, towering, rose–hearted dusk of the the great church. At some altars lights flickered uneasily. At some unseen side altar mass was going on, and a strange ragged music fluttered out on the incense–dusk of the great and lofty interior, which was all shadow, all shadow, hung round with jewel tablets of light. Particularly beautiful the great east bay, above the great altar. And all the time, over the big–patterned marble floor, the faint click and rustle of feet coming and going, coming and going, like shallow uneasy water rustled back and forth in a trough. A white dog trotted pale through the under–dusk, over the pale, big–patterned floor. Aaron came to the side altar where mass was going on, candles ruddily wavering. There was a small cluster of kneeling women— a ragged handful of on–looking men—and people wandering up and wandering away, young women with neatly dressed black hair, and shawls, but without hats; fine young women in very high heels; young men with nothing to do; ragged men with nothing to do. All strayed faintly clicking over the slabbed floor, and glanced at the flickering altar where the white–surpliced boys were curtseying and the white–and–gold priest bowing, his hands over his breast, in the candle–light. All strayed, glanced, lingered, and strayed away again, as if the spectacle were not sufficiently holding. The bell chimed for the elevation of the Host. But the thin trickle of people trickled the same, uneasily, over the slabbed floor of the vastly–upreaching shadow–foliaged cathedral.

The smell of incense in his nostrils, Aaron went out again by a side door, and began to walk along the pavements of the cathedral square, looking at the shops. Some were closed, and had little notices pinned on them. Some were open, and seemed half–stocked with half–elegant things. Men were carrying newspapers. In the cafes a few men were seated drinking vermouth. In the doorway of the restaurants waiters stood inert, looking out on the streets. The curious heart–eating ennui of the big town on a holiday came over our hero. He felt he must get out, whatever happened. He could not bear it.

Holmes and I had listened spellbound to this extraordinary story. My friend rose now and paced up and down the room, his hands in his pockets, and an expression of the most profound gravity upon his face.

“Is Toller still drunk?” he asked.

“Yes. I heard his wife tell Mrs. Rucastle that she could do nothing with him.”

“That is well. And the Rucastles go out to-night?”

“Yes.”

“Is there a cellar with a good strong lock?”

“Yes, the wine-cellar.”

“You seem to me to have acted all through this matter like a very brave and sensible girl, Miss Hunter. Do you think that you could perform one more feat? I should not ask it of you if I did not think you a quite exceptional woman.”

“I will try. What is it?”

“We shall be at the Copper Beeches by seven o’clock, my friend and I. The Rucastles will be gone by that time, and Toller will, we hope, be incapable. There only remains Mrs. Toller, who might give the alarm. If you could send her into the cellar on some errand, and then turn the key upon her, you would facilitate matters immensely.”

“I will do it.”

“Excellent! We shall then look thoroughly into the affair. Of course there is only one feasible explanation. You have been brought there to personate someone, and the real person is imprisoned in this chamber. That is obvious. As to who this prisoner is, I have no doubt that it is the daughter, Miss Alice Rucastle, if I remember right, who was said to have gone to America. You were chosen, doubtless, as resembling her in height, figure, and the colour of your hair. Hers had been cut off, very possibly in some illness through which she has passed, and so, of course, yours had to be sacrificed also. By a curious chance you came upon her tresses. The man in the road was undoubtedly some friend of hers — possibly her fiance — and no doubt, as you wore the girl’s dress and were so like her, he was convinced from your laughter, whenever he saw you, and afterwards from your gesture, that Miss Rucastle was perfectly happy, and that she no longer desired his attentions. The dog is let loose at night to prevent him from endeavouring to communicate with her. So much is fairly clear. The most serious point in the case is the disposition of the child.”

“What on earth has that to do with it?” I ejaculated.

“My dear Watson, you as a medical man are continually gaining light as to the tendencies of a child by the study of the parents. Don’t you see that the converse is equally valid. I have frequently gained my first real insight into the character of parents by studying their children. This child’s disposition is abnormally cruel, merely for cruelty’s sake, and whether he derives this from his smiling father, as I should suspect, or from his mother, it bodes evil for the poor girl who is in their power.”

“I am sure that you are right, Mr. Holmes,” cried our client. “A thousand things come back to me which make me certain that you have hit it. Oh, let us lose not an instant in bringing help to this poor creature.”