He had chosen for himself a small room located in the thick outer wall,
between the two principal doors, and which, in former years, had been
the watchman's quarters. A peep-hole opened upon the bridge; another on
the court. In one corner, there was an opening to a tunnel.

"I believe you told me, Monsieur le Baron, that this tunnel is the only
subterranean entrance to the castle and that it has been closed up for
time immemorial?"

"Yes."

"Then, unless there is some other entrance, known only to Arsene Lupin,
we are quite safe."

He placed three chairs together, stretched himself upon them, lighted
his pipe and sighed:

"Really, Monsieur le Baron, I feel ashamed to accept your money for such
a sinecure as this. I will tell the story to my friend Lupin. He will
enjoy it immensely."

The baron did not laugh. He was anxiously listening, but heard nothing
save the beating of his own heart. From time to time, he leaned over the
tunnel and cast a fearful eye into its depths. He heard the clock strike
eleven, twelve, one.

Suddenly, he seized Ganimard's arm. The latter leaped up, awakened from
his sleep.

"Do you hear?" asked the baron, in a whisper.

"Yes."

"What is it?"

"I was snoring, I suppose."

"No, no, listen."

"Ah! yes, it is the horn of an automobile."

"Well?"

"Well! it is very improbable that Lupin would use an automobile like a
battering-ram to demolish your castle. Come, Monsieur le Baron, return
to your post. I am going to sleep. Good-night."

That was the only alarm. Ganimard resumed his interrupted slumbers, and
the baron heard nothing except the regular snoring of his companion. At
break of day, they left the room. The castle was enveloped in a profound
calm; it was a peaceful dawn on the bosom of a tranquil river. They
mounted the stairs, Cahorn radiant with joy, Ganimard calm as usual.
They heard no sound; they saw nothing to arouse suspicion.

"What did I tell you, Monsieur le Baron? Really, I should not have
accepted your offer. I am ashamed."

He unlocked the door and entered the gallery. Upon two chairs, with
drooping heads and pendent arms, the detective's two assistants were
asleep.

"Tonnerre de nom d'un chien!" exclaimed Ganimard. At the same moment,
the baron cried out:

"The pictures! The credence!"

He stammered, choked, with arms outstretched toward the empty places,
toward the denuded walls where naught remained but the useless nails
and cords. The Watteau, d