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 members of a notorious gang responsible for a payroll robbery.

In the old Montana mining camp of Lucky Lode, the young detectives puzzle over a series of mysterious events. A piano-playing ghost haunts the long-abandoned dance hall; eerie blue lights flash from the hilltop cemetery in the dark of night; strange men arrange a meeting at Shadow the Bear, and a suspect disappears through a curtain of frozen ice.

Are these events related to the men who kidnapped the boys in Chicago on their way to Montana? Who booby-trapped the helicopter which flew the young detectives to the ghost town? And what ever happened to Bart Dawson who seemingly deserted his gold-mining partners twenty-five years ago? Frank and Joe cleverly fit the scattered pieces of this dangerous puzzle into place, and come up with an astonishing solution.