The Mystery at Devil's Paw — Franklin W. Dixon

When Frank and Joe Hardy receive a telegram from Tony Prito in Alaska telling them that his life is in jeopardy, they immediately make plans to fly to Tony's rescue.  Unknown enemies dog the Hardys and their pal Chet Morton even before they start the 4,000 mile journey. Puzzling questions lead the Hardys into dangerous sleuthing in the wilderness of Alaska and British Columbia. The astounding secret that the young detectives uncover, in the shadow of the forbidding mountain peak Devil's Paw, winds up one of the most perilous adventures they have ever encountered.