Timber wolves, a Rocky Mountain blizzard, and a mine cave-in are only a few of the perils Frank and Joe Hardy encounter during their search for the principal members of a notorious gang responsible for a payroll robbery. Clue by clue, Frank and Joe cleverly fit into place the scattered pieces of this dangerous puzzle and come up with the astonishing solution.

Frank and Joe solve a mystery involving the disappearance of a professor, a hot-tempered hermit, sabotage at the new Bayport Coastal Radar Station, and the Honeycomb Caves.