John Locke, aka HammerLocke, an expert in guerilla tactics. The wealthy family of Herbert "Herbie" Ridley hires Locke to chaperone the wimpy teenager on a sojourn to Italy, where the tough hero is severely tested. Outnumbered and outfoxed, Locke is helpless when a gang kidnaps Herbie in Florence. A lovely woman, Carla, offers to help him find the boy, and he accepts, although he suspects she may be leading him into a trap. Racing through town after town with Carla, Locke leaves many victims of his machismo behind before reaching the lair where his escort's game plan becomes clear.