“Well, well, we have made a beginning. I should not expect any fresh developments until next Tuesday. In the meantime we can only keep in touch with friend Bennett and enjoy the amenities of this charming town.”

In the morning Mr. Bennett slipped round to bring us the latest report. As Holmes had imagined, times had not been easy with him. Without exactly accusing him of being responsible for our presence, the professor had been very rough and rude in his speech, and evidently felt some strong grievance. This morning he was quite himself again, however, and had delivered his usual brilliant lecture to a crowded class. “Apart from his queer fits,” said Bennett, “he has actually more energy and vitality than I can ever remember, nor was his brain ever clearer. But it’s not he — it’s never the man whom we have known.”

“I don’t think you have anything to fear now for a week at least,” Holmes answered. “I am a busy man, and Dr. Watson has his patients to attend to. Let us agree that we meet here at this hour next Tuesday, and I shall be surprised if before we leave you again we are not able to explain, even if we cannot perhaps put an end to, your troubles. Meanwhile, keep us posted in what occurs.”

I saw nothing of my friend for the next few days, but on the following Monday evening I had a a short note asking me to meet him next day at the train. From what he told me as we travelled up to Camford all was well, the peace of the professor’s house had been unruffled, and his own conduct perfectly normal. This also was the report which was given us by Mr. Bennett himself when he called upon us that evening at our old quarters in the Chequers. “He heard from his London correspondent to-day. There was a letter and there was a small packet, each with the cross under the stamp which warned me not to touch them. There has been nothing else.”

“That may prove quite enough,” said Holmes grimly. “Now, Mr. Bennett, we shall, I think, come to some conclusion tonight. If my deductions are correct we should have an opportunity of bringing matters to a head. In order to do so it is necessary to hold the professor under observation. I would suggest, therefore, that you remain awake and on the lookout. Should you hear him pass your door, do not interrupt him, but follow him as discreetly as you can. Dr. Watson and I will not be far off. By the way, where is the key of that little box of which you spoke?”

“Upon his watch-chain.”

“I fancy our researches must lie in that direction. At the worst the lock should not be very formidable. Have you any other able-bodied man on the premises?”

“There is the coachman, Macphail.”

“Where does he sleep?”

“Over the stables.”

“We might possibly want him. Well, we can do no more until we see how things develop, Good-bye — but I expect that we shall see you before morning.”

It was nearly midnight before we took our station among some bushes immediately opposite the hall door of the professor. It was a fine night, but chilly, and we were glad of our warm overcoats. There was a breeze, and clouds were scudding across the sky, obscuring from time to time the half-moon. It would have been a dismal vigil were it not for the expectation and excitement which carried us along, and the assurance of my comrade that we had probably reached the end of the strange sequence of events which had engaged our attention.

"The house in the Square Lamartine is occupied by Prasville's men."

"Don't worry, Sebastiani. I shall get in. If they don't open the door, there's always the window. And, if the window won't open, I shall arrange with one of Prasville's men. It's a question of money, that's all. And, thank goodness, I shan't be short of that, henceforth! Good-night, Daubrecq."

He went out, accompanied by Sebastiani, and the heavy door closed after them.

Lupin at once effected his retreat, in accordance with a plan which he had worked out during this scene.

The plan was sunple enough: to scramble, by means of his rope, to the bottom of the cliff, take his friends with him, jump into the motor-car and attack d'Albufex and Sebastiani on the deserted road that leads to Aumale Station. There could be no doubt about the issue of the contest. With d'Albufex and Sebastiani prisoners; it would be an easy matter to make one of them speak. D'Albufex had shown him how to set about it; and Clarisse Mergy would be inflexible where it was a question of saving her son.

He took the rope with which he had provided himself and groped about to find a jagged piece of rock round which to pass it, so as to leave two equal lengths hanging, by which he could let himself down. But, when he found what he wanted, instead of acting swiftly - for the business was urgent - he stood motionless, thinking. His scheme failed to satisfy him at the last moment.

"It's absurd, what I'm proposing," he said to himself. "Absurd and illogical. How can I tell that d'Albufex and Sebastiani will not escape me? How can I even tell that, once they are in my power, they will speak? No, I shall stay. There are better things to try... much better things. It's not those two I must be at, but Daubrecq. He's done for; he has not a kick left in him. If he has told the marquis his secret, there is no reason why he shouldn't tell it to Clarisse and me, when we employ the same methods. That's settled! We'll kidnap the Daubrecq bird." And he continued, "Besides, what do I risk? If the scheme miscarries, Clarisse and I will rush off to Paris and, together with Prasville, organize a careful watch in the Square Lamartine to prevent d'Albufex from benefiting by Daubrecq's revelations. The great thing is for Prasville to be warned of the danger. He shall be."

The church-clock in a neighbouring village struck twelve. That gave Lupin six or seven hours to put his new plan into execution. He set to work forthwith.

When moving away from the embrasure which had the window at the bottom of it, he had come upon a clump of small shrubs in one of the hollows of the cliff. He cut away a dozen of these, with his knife, and whittled them all down to the same size. Then he cut off two equal lengths from his rope. These were the uprights of the ladder. He fastened the twelve little sticks between the uprights and thus contrived a rope-ladder about six yards long.

When he returned to this post, there was only one of the three sons beside Daubrecq's bed in the torture-chamber. He was smoking his pipe by the lamp. Daubrecq was asleep.