Spurred on by the death of his drug-addicted sister at the hands of ruthless narcotics kingpin Frank McNally (Trevor Howard), U.S. drug enforcement agent Charles Sturgis (Victor Mature) embarks on an investigation that takes him from New York to London, Lisbon, Rome, Naples and finally Athens in pursuit of McNally's shapely associate, Gina Broger (Anita Ekberg). With her arrest by Interpol, Gina agrees to help Sturgis track McNally and
