here were no
big territorial changes, although there were many attacks on a grand
scale at Ypres, at Verdun, on the Somme, and in the plain of Flanders.
But this period, tedious though it was, came to an end at last in the
great German retreat. Then came for Max and Dale the crucial period of
all their long and patient scheming to outwit their own special enemy,
Otto von Schenkendorf, the manager of the Durend works.

When the great retreat began, Max and Dale were at Liege, on the spot.
At the gates of the works they watched the serried ranks of workmen and
workwomen as they trudged out in response to the manager's orders that
the works must be closed and that all workers of German nationality or
sympathies must retire across the frontier. The anger and consternation
in their faces were a treat to see, after the long years of their
arrogance towards men and women of Belgian nationality. The war was
virtually over--so said their faces--and many of them were doubtless
dreading lest infamies, similar to those wreaked on the helpless
Belgians, might be perpetrated in _their_ towns and villages.

As the crowd thinned, Max and Dale caught sight of the manager,
accompanied by a German officer, seated in a great grey motor just
inside the gates, apparently waiting for the last workman to file out
and away. The guard of soldiers was still there, standing stiffly to
attention, and it seemed to Max that there was an air of tension about
them all, as though something was about to happen. He could well guess
what. Suddenly, in the distance, there came the sound of dropping
rifle-shots.

"They've cut it pretty fine, if those shots mean the advance guard of
the Allies," remarked Max in a voice tense with excitement. "The works
are clear of the workmen; now for the last great act. Then the curtain!"

Herr Schenk--as we shall continue to call him--stood up in his car and
shouted to the officer of the guard:

"You have your instructions, Lieutenant. Act upon them now without
delay."

The officer saluted, turned about with military precision, and strode
into the guard-room.

Herr Schenk resumed his seat, nodded to the chauffeur, and the car moved
slowly through the gates into the road. Max thought he was about to
leave the works for good and all, but the car stopped at the side of the
road a hundred yards or so from the gates, and all in her stood up and
gazed back in the direction of the works. In the distance, but nearer
now,