The Hardy boys and their father solve a mystery involving inexplicable crashes of highspeed race cars being used to test an experimental turbine motor.

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.

The Hardy boys' investigation of a museum robbery in England arouses the anger of a coven of black witches.