A riddle never to be read:  Sofia only knew that, finding herself awake, she got up, donned negligee and slippers, and set her feet upon the way appointed without its occurring to her that the way was strange, without stopping to question why or whether.

If independent volition, sensible or subliminal, were absent, it could hardly have been apparent.  Sofia herself was not aware of its suspense or supersession.  She knew quite well what she was doing, her every action was direct and decided, the goal alone remained obscure.  She only knew that somewhere, somehow, something was going wrong without her, and her presence was required to set it right.

Letting herself out into the corridor, she drew the door to behind her, but left it unlatched; with what object, she did not know.  But the lateness of the hour, the stillness of the sleeping household, made it seem quite in order that she should pause to look cautiously this way and that and make sure that nobody else was astir to spy upon her or challenge the purpose of this as yet aimless nocturnal flitting.

There was nobody that she could see.

Down the corridor, then, never asking why that way, like a ghost in haste she sped, but as she drew near to a certain door found her pace faltering.  Sofia knew that door; through it Lady Randolph West herself had introduced the girl to her boudoir, not two hours since, when chance, or Fate, or the smooth working out of malicious mortal machinations had moved the two women simultaneously to seek their quarters for the night.  And in the boudoir Sofia had spent the quarter of an hour before going on to her own room and bed, civilly attending to vapid chatter and admiring as in duty bound the admirable jewels of the family.

Now she saw the door a few inches ajar with, beyond it, a dim glow.  The circumstance seemed singular, because—­now that she remembered—­when Sofia had expressed perfunctory curiosity concerning what precautions were taken to safeguard the jewels, Lady Randolph West had airily informed her that she considered insurance to their appraised value plus a stout lock on the boudoir door better than any strong-box as yet devised by the ingenuity of man.

“There’s the safe they’re kept in, of course,” the lady had declared—­“but, my dear, a cardboard box will do as well when any burglar who knows his business makes up his mind to get at my trinkets.  I never even trouble to lock the thing.  I’d rather lose the jewels—­and collect the insurance money—­than be frightened out of my wits by hearing it blown open.  No, thanks ever so:  any cracksman skillful enough to pick the lock on the door may bag his loot and go in peace for all of me!”

Impulse, at least she called it that, moved Sofia to approach and cautiously open the door still wider.