The duke chuckled.
"Yes, he's back again," said he, "so you must make the best of it, my girl.

Where's the duchess ?" "In--in--in her sitting-room, M.le Duc." "'In--in--in,'" he echoed mockingly.

Then he stepped swiftly across the hall and flung the door suddenly open.

I believe he thought that he really had surprised Jean's slow aged scamper ahead of him.
"Silence for your life!" I had time to whisper to Suzanne; and then I followed him.

There might be more "fun" to come.
The duchess was sitting with a book in her hand.