he wanted to know and so he is going--where? To the
castle?"

He was within touch of the goal. He felt it by a sort of agonizing
gladness that uplifted his whole being.

The man plunged into a dark wood overhanging the river and then
appeared once more in the full light, where the path met the horizon.

When Beautrelet, in his turn, emerged from the wood, he was greatly
surprised no longer to see the man. He was seeking him with his eyes
when, suddenly, he gave a stifled cry and, with a backward spring, made
for the line of trees which he had just left. On his right, he had seen
a rampart of high walls, flanked, at regular distances, by massive
buttresses.

It was there! It was there! Those walls held his father captive! He had
found the secret place where Lupin confined his victim.

He dared not quit the shelter which the thick foliage of the wood
afforded him. Slowly, almost on all fours, he bore to the right and in
this way reached the top of a hillock that rose to the level of the
neighboring trees. The walls were taller still. Nevertheless, he
perceived the roof of the castle which they surrounded, an old Louis
XIII. roof, surmounted by very slender bell-turrets arranged
corbel-wise around a higher steeple which ran to a point.

Beautrelet did no more that day. He felt the need to reflect and to
prepare his plan of attack without leaving anything to chance. He held
Lupin safe; and it was for Beautrelet now to select the hour and the
manner of the combat.

He walked away.

Near the bridge, he met two country-girls carrying pails of milk. He
asked:

"What is the name of the castle over there, behind the trees?"

"That's the Chateau de l'Aiguille, sir."

He had put his question without attaching any importance to it. The
answer took away his breath:

"The Chateau de l'Aiguille?--Oh!--But in what department are we? The
Indre?"

"Certainly not. The Indre is on the other side of the river. This side,
it's the Creuse."

Isidore saw it all in a flash. The Chateau de l'Aiguille! The
department of the Creuse! L'AIGUILLE CREUSE! The Hollow Needle! The
very key to the document! Certain, decisive, absolute victory!

Without another word, he turned his back on the two girls and went his
way, tottering like a drunken man.

CHAPTER SIX

AN HISTORIC SECRET

Beautrelet's resolve was soon taken: he would act alone. To inform the
police was too dangerous. Apart from the fact that he could only offer
p