“I want to speak to you,” said Max, in a low voice.

But all her boldness of their first interview, her coquetry of the second, her quiet caution of the third had disappeared.  She was now frightened, shy, anxious to get away.

“Oh, why did you come back?  Why did you come back?  Go away at once and never come here again.  Haven’t you got a lesson?”

Her voice broke; her anxiety was visible.  Max was touched, more interested than ever.

“I can’t go away,” he whispered back, “until I have spoken to you about something which is very serious.  Can’t you come out on the wharf, somewhere where we can talk without anybody over-hearing?”

“Oh, no, oh, no.  I must go in.  And you must go.  Are you a fool,” and she stamped her foot with sudden impatience, “to be so persistent?”

“A fool?” echoed Max, half to himself.  “By Jove, I think I am.  Look here,” and he bent down so that he might whisper very close to her ear; “I must set the police on this place, you know; but I want you to get away out of it first.”

She listened in silence.  She waited for him to say more.  But he was waiting on his side for the protests he expected.  At last she laughed to herself derisively.

“All right,” said she.  “Set the police on us by all means.  Oh, do—­do!  But—­just mention first to your friend, Mr. Horne, that that’s what you’re going to do.  Just mention it to him, and see the thanks you’ll get for your trouble!”

These words came upon Max with a great shock.  In the excitement of his own adventures in this place, he had quite forgotten his friend, Dudley Horne, and the errand which had first brought him into the neighborhood.  He had forgotten, also, what he had from the first only half believed—­the girl’s words connecting Dudley with a murder committed within those walls.

Now that the remembrance was thus abruptly brought back to him, he felt as if he wanted to gasp for breath.  Carrie watched him, and presently made a sign to him to follow her.  Scrambling out to the open space on the wharf, she made for the spot close to the water where Max had stood to watch the man whom Carrie had called “Dick.”

When Max came up to her, the girl was standing close under the eaves of the outhouse on the bank, leaning against the wall.  He could scarcely see anything of her face in the darkness, but he was struck by something strangely moving in the tones of her voice as she broke the silence.

“Look here,” she said, “I want you to make me a promise.  Come, it ought not to be difficult; for I got you out of a nice mess; remember that.  You’ve got to give me your word that you will say nothing about your adventures to-day, either to the police or to anybody else.”

“I can’t promise that.  And why on earth do you want me to do so?  Surely you can have no real sympathy with the people who do the things that are done in there—­”