e could not be persuaded to
indicate to the curious youth just what to expect.

Whatever was to occur, Robert was assured that he would witness; in
fact, he would be a necessary feature to the mysterious plans of the
detective.

Stimulated, therefore, by these occult hints and the lively prospect
they introduced, the young man developed a clandestine emotion of weird
anticipation, which he readily accredited to an unsuspected fitness for
intrigue.

Gratz, in the meantime, having primed the young enthusiast, maintained
an irritating silence, and when an hour had passed in this spiritless
fashion Robert was electrified by the solitary word "Now!" from the lips
of the enigmatical Gratz.

Unable to comprehend the significance of the subdued exclamation, Robert
nevertheless followed the detective with confiding docility, and the
pair hastened down a flight of stairs which conducted them to the main
hallway.

From this Gratz proceeded to a door directly beneath the stairway which
they had just traversed, and which opened upon another short series of
steps that concluded in the cellar.

Descending these, the two hastened along the chill floor and presently
paused by the main coal-bin in which the widow stored her fuel.

With an impressive injunction to silence, Gratz indicated the course
which Robert was expected to pursue, and in the recess created by a
flight of disused stairs the two secreted themselves.

It was pitch dark.

Neither of the watchers could see the other, and communication was only
maintained by the reassuring pressure of the hand of the detective upon
the arm of the excited Robert.

At last the latter ventured to inquire in a whisper what it was that
Gratz expected to discover.

"The solution of the puzzle," replied the other in the same tone.

"The thief?" asked Robert.

"No, the accessory," was the reply; "but do not ask any further
questions; you will be treated to the surprise of your life in a little
while, unless I am much mistaken."

Scarcely had the detective uttered these words when the faint click of a
door-latch was borne to their ears from the direction of the stairway
they had just descended.

The next moment a dim ray of light flickered into the darkness, and a
figure vaguely shadowed its grotesque disproportion on the walls just
behind as it crept, with cautious lightness, step by step down the
stairs.

At last it reached the floor and moved in the direction of the bin.