A series of grisly murders plague a small mountain community and the sheriff suspects a local scientist whom he dislikes. Together with a former professor and the professor's pretty daughter, the scientist sets about solving the crimes and discovers the killer is an oversized 16th century conquistador, resurrected by a lightning bolt from his mountain grave.

Glenn Manning, "The Amazing Colossal Man," believed dead after falling from the Hoover Dam, reemerges in rural Mexico, brain damaged, disfigured, and very angry.