Sheriff Les Martin (Cornel Wilde) is puzzled in his investigation of three mysterious murders near the Grand Canyon. Lacking any clues, Les enlists his girlfriend Janice Kendon (Victoria Shaw), daughter of a retired mine owner, and bartender Scotty O'Brien (Mickey Shaughnessy) to help with the case. When Janice's brother, Bob (Rian Garrick), leads Les and Janice to a rendezvous with an associate in the middle of it all, Sheriff Martin is drawn into a dangerous -- and deadly -- chase high above the Grand Canyon's floor. Newly remastered.

A well-dressed older man drives a car along the winding mountain road adjacent to the Grand Canyon. Another man lies in wait for him where the road ends. They fight, and the car and one of the men plunge into the mile-deep gorge. Thus begins a series of four killings that fall into the lap of newly hired Mojave County deputy Les Martin (Cornel Wilde) and his boss, Sheriff Edwards (Edgar Buchanan). Les is an experienced homicide detective trying to redeem himself and his career after a series of personal tragedies and professional disasters, unsteady in his confidence and uncertain of his ability -- the only people he's especially close to are the sheriff who hired him and Scotty (Mickey Shaughnessy), the big-hearted keeper of the local tavern. And complicating his investigation of the murder case at hand is his constant crossing of paths with the beautiful, wealthy Janice Kendon (Victoria Shaw), who seems to have a knack for turning up around every corner of this case. He has to sort out his feelings about her and work out what the murders have to do with the one clue left behind by one of the victims, about the "dancing bucket" that carries men and material more than 7,000 feet across the mile-high chasm.