made
their acquaintance before.

Hal Paine and Chester Crawford, two American lads, their ages being about
18 and 19, had seen considerable service in the great European war--the
greatest war of all time. They had been in Berlin when Germany had
declared war upon Russia and France and with Hal's mother had attempted
to make their way from that country. The mother had been successful; but
Hal and Chester got into trouble and had been left behind.

Fortunately, however, two young officers, Major Raoul Derevaux, a
Frenchman, and Captain Harry Anderson, an Englishman, had come to their
assistance--reciprocating a good turn done them by the two lads a day
before--and together, after some difficulties, they succeeded in
reaching Liege, Belgium, just in time to take part in its heroic defense
against the first German hordes that violated the neutrality of the
little buffer country.

Both had distinguished themselves by their coolness and bravery under
fire, and had found favor in the eyes of the Belgian commander, as
related in "The Boy Allies at Liege." Later they had rendered themselves
invaluable in carrying dispatches.

Following their adventures in this campaign they saw service with the
British forces on the continent, as told in "The Boy Allies on the Firing
Line." In this campaign they had been instrumental in foiling a
well-planned German coup, which would have resulted in a severe blow to
the British had it been put through.

Also, while scouting in the enemy's domain, Hal and Chester had unearthed
a conspiracy that threatened the destruction of a whole French army
corps. By prompt action the lads prevented this and won the
congratulations of General Joffre, the French commander-in-chief.

It was through information gleaned by the lads that the British army was
finally able to surprise the enemy and advance to the east shore of the
River Marne, after a struggle that had lasted for two weeks.

In a battle following this decisive engagement--while returning from a
successful raid--Captain Harry Anderson, who had accompanied them, was
critically wounded and, together with Hal and Chester, taken prisoner.
Hal and Chester, with a French army dog they had rescued from the wrath
of a German officer, were taken almost immediately to Berlin.

There, while strolling about the street one day in company with the
German officer in whose charge they had been placed, they were made, to
their surprise, the bearer of an imp