The road through the river-valley was little used, and nobody came to interrupt the work. The night was dark, the sky heavy with moveless clouds.

Lupin gave the Masher and the Growler their final instructions and said, with a laugh:

"I can't tell you how amused I am at the thought of seeing Daubrecq's face when they proceed to take his scalp or slice his skin into ribbons. Upon my word, it's worth the journey."

Clarisse also had taken a seat in the boat. He said to her:

"Until we meet again. And, above all, don't stir. Whatever happens, not a movement, not a cry."

"Can anything happen?" she asked.

"Why, remember the Sire de Tancarville! It was at the very moment when he was achieving his object, with his true love in his arms, that an accident betrayed him. But be easy: I shall be all right."

She made no reply. She seized his hand and grasped it warmly between her own.

He put his foot on the ladder and made sure that it did not sway too much. Then he went up.

He soon reached the top rung.

This was where the dangerous ascent began, a difficult ascent at the start, because of the excessive steepness, and developing, mid-way, into an absolute escalade.

Fortunately, here and there were little hollows, hollows in which his feet found a resting-place, and projecting stones, to which his hands clung. But twice those stones gave way and he slipped; and twice he firmly believed that all was lost. Finding a deeper hollow, he took a rest. He was worn out, felt quite ready to throw up the enterprise, asked himself if it was really worth while for him to expose himself to such danger:

"I say!" he thought. "Seems to me you're showing the white feather, Lupin, old boy. Throw up the enterprise? Then Daubrecq will babble his secret, the marquis will possess himself of the list, Lupin will return empty-handed, and Gilbert... "

The long rope which he had fastened round his waist caused him needless inconvenience and fatigue. He fixed one of the ends to the strap of his trousers and let the rope uncoil all the way down the ascent, so that he could use it, on returning, as a hand-rail.

Then he once more clutched at the rough surface of the cliff and continued the climb, with bruised nails and bleeding fingers. At every moment he expected the inevitable fall. And what discouraged him most was to hear the murmur of voices rising from the boat, murmur so distinct that it seemed as though he were not increasing the distance between his companions and himself.

And he remembered the Sire de Tancarville, alone, he too, amid the darkness, who must have shivered at the noise of the stones which he loosened and sent bounding down the cliff. How the least sound reverberated through the silence! If one of Daubrecq's guards was peering into the gloom from the Lovers' Tower, it meant a shot... and death.

And he climbed... he climbed... He had climbed so long that he ended by imagining that the goal was passed. Beyond a doubt, he had slanted unawares to the right or left and he would finish at the patrol-path. What a stupid upshot! And what other upshot could there be to an attempt which the swift force of events had not allowed him to study and prepare?

“His methods are irregular, no doubt, like my own. The irregulars are useful sometimes, you know. You, for example, with your compulsory warning about whatever he said being used against him, could never have bluffed this rascal into what is virtually a confession.”

“Perhaps not. But we get there all the same, Mr. Holmes. Don’t imagine that we had not formed our own views of this case, and that we would not have laid our hands on our man. You will excuse us for feeling sore when you jump in with methods which we cannot use, and so rob us of the credit.”

“There shall be no such robbery, MacKinnon. I assure you that I efface myself from now onward, and as to Barker, he has done nothing save what I told him.”

The inspector seemed considerably relieved.

“That is very handsome of you, Mr. Holmes. Praise or blame can matter little to you, but it is very different to us when the newspapers begin to ask questions.”

“Quite so. But they are pretty sure to ask questions anyhow, so it would be as well to have answers. What will you say, for example, when the intelligent and enterprising reporter asks you what the exact points were which aroused your suspicion, and finally gave you a certain conviction as to the real facts?”

The inspector looked puzzled.

“We don’t seem to have got any real facts yet, Mr. Holmes. You say that the prisoner, in the presence of three witnesses, practically confessed by trying to commit suicide, that he had murdered his wife and her lover. What other facts have you?”

“Have you arranged for a search?”

“There are three constables on their way.”

“Then you will soon get the clearest fact of all. The bodies cannot be far away. Try the cellars and the garden. It should not take long to dig up the likely places. This house is older than the water-pipes. There must be a disused well somewhere. Try your luck there.”

“But how did you know of it, and how was it done?”

“I’ll show you first how it was done, and then I will give the explanation which is due to you, and even more to my longsuffering friend here, who has been invaluable throughout. But, first, I would give you an insight into this man’s mentality. It is a very unusual one — so much so that I think his destination is more likely to be Broadmoor than the scaffold. He has, to a high degree, the sort of mind which one associates with the mediaeval Italian nature rather than with the modern Briton. He was a miserable miser who made his wife so wretched by his niggardly ways that she was a ready prey for any adventurer. Such a one came upon the scene in the person of this chess-playing doctor. Amberley excelled at chess — one mark, Watson, of a scheming mind. Like all misers, he was a jealous man, and his jealousy became a frantic mania. Rightly or wrongly, he suspected an intrigue. He determined to have his revenge, and he planned it with diabolical cleverness. Come here!”