ise. Their
surprise increased as they observed that the light moved along the
floor at a pace about equal to their own.

Ned thought that he could faintly discern the feet of the person
carrying the light, but was unable to learn anything of the character
of the person. He was torn between his desire to escape from the
apartment and the wish to learn the identity of the stranger.

Only a few steps had been taken by the stranger before the light was
extinguished. Instantly the three boys halted.

"S-s-sh!" came a warning hiss. "Be mighty careful now of your
conversation and your footsteps. Keep as quiet as possible and follow
me closely. We are all in extreme danger!"

In spite of his efforts at self-control, Ned's muscles trembled and he
found it difficult to walk steadily. Assuming that his chums were in
like plight, the lad summoned all his courage and reached out a
reassuring hand to the others. The contact with his friends seemed to
restore the equilibrium that had been Ned's most valuable asset in
times of stress and danger in his many adventures.

Long afterwards the boy declared that in all his experiences that
compassed many strange and hazardous enterprises in the United States,
Canada, Mexico, the Philippines, China and other countries he had never
felt so keenly the need of aid as he did at that moment.

Not for long, however, were the boys permitted to consider the peril of
their position. Almost instantly they heard a faint grating sound
directly in front of them. A cold draught of damp, musty air struck
their faces, and they understood that a door had been opened into some
other apartment. The odor of the incoming air told them plainly that
the next apartment was also underground, and they surmised that it had
not recently been occupied.

"Come!" was the command borne to their ears in the faintest of whispers
from the person leading the way.

Unhesitatingly the lads advanced. Jack had taken but a couple of steps
before he collided with some solid object. The shock of contact
brought forth a grunt of surprise. At the same moment Harry went
through a similar experience. Ned met no resistance and nearly lost
his hold of the others before he recovered his balance.

"Gee!" Jack whispered, "I've hit a wall!"

"Here, too!" put in Harry, lowering his whisper to a mere breath.

"Single file, lock step," directed Ned.

Jack and Harry fell in behind their Scout Master obediently, and the