Four Boy Scouts, of the Beaver Patrol, Chicago, were in camp on
Moose river. They were all athletic young fellows, not far from
seventeen years of age, and were dressed in the khaki uniform
adopted by the Boy Scouts of America.

If you take a map of the British Northwest Territories and look up
Moose river, you will discover that it runs through nearly three
hundred miles of wilderness, from Lake Missinale to Moose Bay. The
reader will well understand, then, how far "Sandy" Green, Will
Smith, George Benton and Tommy Gregory had traveled from
civilization.

The camp of the Boy Scouts was situated some fifty miles up the
river from Moose Factory, a trading point famous in old Indian days
for its adventurous spirits and its profits to the factors. Those
who have read the preceding books of this series will doubtless
remember the four Boy Scouts named above. Together they had
visited the Pictured Rocks of Old Superior, the Everglades of
Florida, and the great Continental Divide.

During all their journeys the boys had shown courage and
resourcefulness beyond their years, and because of these qualities
they had been chosen, by Mr. Horton, a noted criminal lawyer of
Chicago, to undertake a difficult and dangerous mission to the
Hudson Bay country.

They had traveled by way of the Canadian Pacific to Missanabie,
from which point they had proceeded to Lake Missinale. Here they
had purchased a "Mackinaw," a great flat-bottomed craft, in which
to transport their tents and supplies down Moose river to the bay