Expert mountain-guide Maciste lives in the Dolomites. He dotes on his young nephew Hans, the illegitimate son of his sister, who died of a broken heart for the dishonour of being seduced and abandoned. Maciste’s bitter rival is the sinister Schultz, a smuggler in search of easy money who teams up with two adventurers: Müller and the mysterious Vanna Dardos. Schultz’s plan is to steal the design for a revolutionary aviation project that engineer Riccardo Ewert is finishing in the peace and quiet of his mountain chalet. Thanks to Maciste the plan is thwarted and Müller and Schultz die overwhelmed by an avalanche while escaping through the mountains.