who had penetrated through that issue: Celts, Gauls, Romans, Normans, Englishmen, Frenchmen, barons, dukes, kings—and, after all of them, Arsene Lupin—and, after Lupin, himself, Beautrelet. He felt that his brain was slipping away from him. His eyelids fluttered. He fell fainting and rolled to the bottom of the slope, to the very edge of the precipice.
His task was done, at least the task which he was able to accomplish alone, with his unaided resources.
That evening, he wrote a long letter to the chief of the detective service, giving a faithful account of the results of his investigations and revealing the secret of the Hollow Needle. He asked for assistance to complete his work and gave his address.
While waiting for the reply, he spent two consecutive nights in the Chambre des Demoiselles. He spent them overcome with fear, his nerves shaken with a terror which was increased by the sounds of the night. At every moment, he thought he saw shadows approach in his direction. People knew of his presence in the cave—they were coming—they were murdering him!
His eyes, however, staring madly before them, sustained by all the power of his will, clung to the piece of wall.
On the first night, nothing stirred; but, on the second, by the light of the stars and a slender crescent-moon, he saw the door open and figures emerge from the darkness: he counted two, three, four, five of them.
It seemed to him that those five men were carrying fairly large loads. He followed them for a little way. They cut straight across the fields to the Havre road; and he heard the sound of a motor car driving away.
He retraced his steps, skirting a big farm. But, at the turn of the road that ran beside it, he had only just time to scramble up a slope and hide behind some trees. More men passed—four, five men— all carrying packages. And, two minutes later, another motor snorted.
This time, he had not the strength to return to his post; and he went back to bed.
When he woke and had finished dressing, the hotel waiter brought him a letter. He opened it. It contained Ganimard's card.
"At last!" cried Beautrelet, who, after so hard a campaign, was really feeling the need of a comrade-in-arms.
He ran downstairs with outstretched hands. Ganimard took them, looked at him for a moment and said:
"You're a fine fellow, my lad!"
"Pooh!" he said. "Luck has served me."
"There's no such thing as luck with 'him,'" declared the inspector, who always spoke of Lupin in a solemn tone and without mentioning his name.
He sat down:
"So we've got him!"
"Just as we've had him twenty times over," said Beautrelet, laughing.
"Yes, but to-day—"
"To-day, of course, the case is different. We know his retreat, his stronghold, which means, when all is said, that Lupin is Lupin. He can escape. The Etretat Needle cannot."
"Why do you suppose that he will escape?" asked Ganimard, anxiously.
"Why do you suppose that he requires to escape?" replied Beautrelet. "There is nothing to prove that he is in the Needle at present. Last night, eleven of his men left it. He may be one of the eleven."
Ganimard reflected:
"You are right. The great thing is the Hollow Needle. For the rest, let us hope that chance will favor us. And now, let us talk."
He resumed his serious voice, his self-important air and said:
"My dear Beautrelet, I have orders to recommend you to observe the most absolute discretion in regard to this matter."
"Orders from whom?" asked Beautrelet, jestingly. "The prefect of police?"
"Higher than that."
"The prime minister?"
"Higher."
"Whew!"
Ganimard lowered his voice:
"Beautrelet, I was at the Elysee last night. They look upon this matter as a state secret of the utmost gravity. There are serious reasons for concealing the existence of this citadel—reasons of military strategy, in particular. It might become a revictualling centre, a magazine for new explosives, for lately-invented projectiles, for anything of that sort: the secret arsenal of France, in fact."
"But how can they hope to keep a secret like this? In the old days, one man alone held it: the king. To-day, already, there are a good few of us who know it, without counting Lupin's gang."
"Still, if we gained only ten years', only five years' silence! Those five years may be—the saving of us."
"But, in order to capture this citadel, this future arsenal, it will have to be attacked, Lupin must be dislodged. And all this cannot be done without noise."
"Of course, people will guess something, but they won't know. Besides, we can but try."
"All right. What's your plan?"
"Here it is, in two words. To begin with, you are not Isidore Beautrelet and there's no question of Arsene Lupin either. You are and you remain a small boy of Etretat, who, while strolling about the place, caught some fellows coming out of an underground passage. This makes you suspect the existence of a flight of steps which cuts through the cliff from top to bottom."
"Yes, there are several of those flights of steps along the coast. For instance, to the right of Etretat, opposite Benouville, they showed me the Devil's Staircase, which every bather knows. And I say nothing of the three or four tunnels used by the fishermen."
"So you will guide me and one-half of my men. I shall enter alone, or accompanied, that remains to be seen. This much is certain, that the attack must be delivered that way. If Lupin is not in the Needle, we shall fix up a trap in which he will be caught sooner or later. If he is there—"
"If he is there, he will escape from the Needle by the other side, the side overlooking the sea."
"In that case, he will at once be arrested by the other half of my men."
"Yes, but if, as I presume, you choose a moment when the sea is at low ebb, leaving the base of the Needle uncovered, the chase will be public, because it will take place before all the men and women fishing for mussels, shrimps and shell-fish who swarm on the rocks round about."
"That is why I just mean to select the time when the sea is full."
"In that case, he will make off in a boat."
"Ah, but I shall have a dozen fishing-smacks, each of which will be commanded by one of my men, and we shall collar him—"
"If he doesn't slip through your dozen smacks, like a fish through the meshes."
"All right, then I'll sink him."
"The devil you will! Shall you have guns?"
"Why, of course! There's a torpedo-boat at the Havre at this moment. A telegram from me will bring her to the Needle at the appointed hour."
"How proud Lupin will be! A torpedo-boat! Well, M. Ganimard, I see that you have provided for everything. We have only to go ahead. When do we deliver the assault?"
"To-morrow."
"At night?"
"No, by daylight, at the flood-tide, as the clock strikes ten in the morning."
"Capital."
Under his show of gaiety, Beautrelet concealed a real anguish of mind. He did not sleep until the morning, but lay pondering over the most impracticable schemes, one after the other.
Ganimard had left him in order to go to Yport, six or seven miles from Etretat, where, for prudence's sake, he had told his men to meet him, and where he chartered twelve fishing smacks, with the ostensible object of taking soundings along the coast.
At a quarter to ten, escorted by a body of twelve stalwart