inside Mlle. Darcieux's room, bolt the door and don't budge. You quite
understand, don't budge, either of you, whatever happens. I have noticed
that Mlle. Darcieux leaves her dressing-room window ajar, isn't that
so?"

"Yes, it's a habit which I taught her."

"That's the way they'll come."

"And you?"

"That's the way I shall come also."

"And do you know who the villain is?"

Lupin hesitated and then replied:

"No, I don't know.... And that is just how we shall find out. But, I
implore you, keep cool. Not a word, not a movement, _whatever happens_!"

"I promise you."

"I want more than that, doctor. You must give me your word of honour."

"I give you my word of honour."

The doctor went away. Lupin at once climbed a neighbouring mound from
which he could see the windows of the first and second floor. Several of
them were lighted.

He waited for some little time. The lights went out one by one. Then,
taking a direction opposite to that in which the doctor had gone, he
branched off to the right and skirted the wall until he came to the
clump of trees near which he had hidden his motor-cycle on the day
before.

Eleven o'clock struck. He calculated the time which it would take the
doctor to cross the kitchen-garden and make his way into the house.

"That's one point scored!" he muttered. "Everything's all right on that
side. And now, Lupin to the rescue? The enemy won't be long before he
plays his last trump ... and, by all the gods, I must be there!..."

He went through the same performance as on the first occasion, pulled
down the branch and hoisted himself to the top of the wall, from which
he was able to reach the bigger boughs of the tree.

Just then he pricked up his ears. He seemed to hear a rustling of dead
leaves. And he actually perceived a dark form moving on the level thirty
yards away:

"Hang it all!" he said to himself. "I'm done: the scoundrel has smelt a
rat."

A moonbeam pierced through the clouds. Lupin distinctly saw the man take
aim. He tried to jump to the ground and turned his head. But he felt
something hit him in the chest, heard the sound of a report, uttered an
angry oath and came crashing down from branch to branch, like a corpse.

* * * * *

Meanwhile, Doctor Gueroult, following Arsene Lupin's instructions, had
climbed the ledge of the fifth window and groped his way to the first
floor. On reaching Jeanne's room, he tapped lightly, three t