s box they found in the sand.

Then followed that glorious trip to Pine Island. An aunt of Mollie
Billette had turned her bungalow over to the Outdoor Girls for the summer.
During their strenuous adventures the girls had made many friends among
the boys and young men of Deepdale, and four of these had asked and been
granted permission by the girls to accompany them to Pine Island and pitch
their camp in the woods near by.

One of the young men was Allen Washburn, a rising young lawyer and a great
admirer of Betty. Another was Will Ford, Grace's brother, and a third was
his high school chum, Frank Haley. The fourth, Roy Anderson, had been
drawn into the circle chiefly through his admiration for Grace.

During that eventful summer on Pine Island the young people had
accidentally discovered a gypsy cave, concealed by underbrush, and had
succeeded not only in rounding up the band of gypsies but in recovering
several valuable articles that had been stolen from the girls.

Their last adventure, related in the volume directly preceding this one,
and entitled "Outdoor Girls in Army Service," found the girls and boys
again at Pine Island, but under very much altered conditions. America had
entered the great World War and all the boys but Will Ford had
volunteered. Later, the boys were called to Camp Liberty, some distance
from Deepdale, and the girls conceived the plan of opening a Hostess House
for the benefit of the relatives and friends of the boys. The plan worked
out very satisfactorily.

While still at Pine Island the girls and boys had come upon a suspicious
looking man in the woods. Upon finding himself discovered the man had made
his escape, but in his hurry had dropped a letter which the girls found to
their disgust was written in code. They decided that the man must have
been a German spy.

At Camp Liberty the girls succeeded in rounding up the spy, and found, to
their surprise, that Will Ford, who was in the Secret Service, had been
engaged all that time in tracking him to earth. Will, having accomplished
his mission, immediately enlisted.

Now, at the time this story opens, the girls were still at the Hostess
House and looking forward apprehensively to the time, now imminent, when
the boys would be ordered across the sea to fight for the country they
loved.

"I'll go with Grace," volunteered Amy, in answer to Betty's request for
water. "I don't suppose we can find any, but we'll try."

The two girls hurrie