which Lupin occupied at that period and which he
used oftener than any of the others was in the Rue Chateaubriand, near
the Arc de l'Etoile. He was known there by the name of Michel Beaumont.
He had a snug flat here and was looked after by a manservant, Achille,
who was utterly devoted to his interests and whose chief duty was to
receive and repeat the telephone-messages addressed to Lupin by his
followers.

Lupin, on returning home, learnt, with great astonishment, that a woman
had been waiting to see him for over an hour:

"What! Why, no one ever comes to see me here! Is she young?"

"No... I don't think so."

"You don't think so!"

"She's wearing a lace shawl over her head, instead of a hat, and you
can't see her face... She's more like a clerk... or a woman employed in
a shop. She's not well-dressed..."

"Whom did she ask for?"

"M. Michel Beaumont," replied the servant.

"Queer. And why has she called?"

"All she said was that it was about the Enghien business... So I thought
that..."

"What! The Enghien business! Then she knows that I am mixed up in that
business... She knows that, by applying here..."

"I could not get anything out of her, but I thought, all the same, that
I had better let her in."

"Quite right. Where is she?"

"In the drawing-room. I've put on the lights."

Lupin walked briskly across the hall and opened the door of the
drawing-room:

"What are you talking about?" he said, to his man. "There's no one
here."

"No one here?" said Achille, running up.

And the room, in fact, was empty.

"Well, on my word, this takes the cake!" cried the servant. "It wasn't
twenty minutes ago that I came and had a look, to make sure. She was
sitting over there. And there's nothing wrong with my eyesight, you
know."

"Look here, look here," said Lupin, irritably. "Where were you while the
woman was waiting?"

"In the hall, governor! I never left the hall for a second! I should
have seen her go out, blow it!"

"Still, she's not here now..."

"So I see," moaned the man, quite flabbergasted.

"She must have got tired of waiting and gone away. But, dash it all, I
should like to know how she got out!"

"How she got out?" said Lupin. "It doesn't take a wizard to tell that."

"What do you mean?"

"She got out through the window. Look, it's still ajar. We are on the
ground-floor... The street is almost always deserted, in the evenings.
There's no doubt about it."

He had looked around