With only the slender clue of an arrow-shaped tie clasp, Frank and Joe Hardy pick up the trail of a cunning gang of thieves responsible for a wave of jewelry store holdups.

But their investigations are interrupted when a desperate plea for help comes from their widowed cousin who lives on a cattle ranch in New Mexico. Frank, Joe, and their pal Chet Morton fly there immediately. The mysterious disappearance of one cowboy after another has Crowhead Ranch a reputation of being jinxed, and it is quickly being stampeded toward financial ruin.

The young detectives face grave danger before they uncover a plot engineered by the crooked arrow gang. In a dramatic climax Frank, Joe, and Chet aid law-enforcement officers in smashing the highly organized band of criminals, putting an end both to the troubles at Crowhead Ranch and the jewelry-store robberies.