Sabatini smiled.

“You are young, as yet,” he said.  “Life and death seem such terrible things to you, such tragedies, such enormous happenings.  In youth, one loses one’s sense of proportion.  Life seems so vital, the universe so empty, without one’s own personality.  Take a pocketful of cigarettes, my dear Mr. Chetwode, and make your way homeward.  We shall meet again in a day or two, I dare say, and by that time your little nightmare will not seem so terrible.”

“You will let your sister know?” Arnold begged.

“She shall know all that you have told me,” Sabatini promised.  “I do not say that it will interest her—­it may or it may not.  In any case, I thank you for coming.”

Arnold was dismissed with a pleasant nod, and passed out into the streets, now emptying fast.  He walked slowly back to his rooms.  Already the sense of unwonted excitement was passing.  Sabatini’s strong, calm personality was like a wonderful antidote.  After all, it was not his affair.  It was possible, after all, that the man was an ordinary burglar.  And yet, if so, what was Isaac doing with him?  He glanced in front of him to where the lights of the two great hotels flared up to the sky.  Somewhere just short of them, before the window of her room, Ruth would be sitting watching.  He quickened his steps.  Perhaps he should find her before he went to bed.  Perhaps he might even see Isaac come in!

Big Ben was striking the half-hour past midnight as Arnold stood on the top landing of the house at the corner of Adam Street, and listened.  To the right was his own bare apartment; on the left, the rooms where Isaac and Ruth lived together.  He struck a match and looked into his own apartment.  There was a note twisted up for him on his table, scribbled in pencil on a half sheet of paper.  He opened it and read: 

      If you are not too late, will you knock at the door and
      wish me good night?  Isaac will be late.  Perhaps he will
      not be home at all.

He stepped back and knocked softly at the opposite door.  In a moment or two he heard the sound of her stick.  She opened the door and came out.  Her eyes shone through the darkness at him but her face was white and strained.  He shook his head.

“Ruth,” he said, “you heard the time?  And you promised to go to bed at ten o’clock!”

She smiled.  He passed his arm around her, holding her up.

“To-night I was afraid,” she whispered.  “I do not know what it was but there seemed to be strange voices about everywhere.  I was afraid for Isaac and afraid for you.”

“My dear girl,” he laughed, “what was there to fear for me?  I had a very good dinner with a very charming man.  Afterwards, we went to a music-hall for a short time, I went back to his rooms, and here I am, just in time to wish you good night.  What could the voices have to tell you about that?”

She shook her head.