Ivy Meeropol, the granddaughter of Julius and Ethel Rosenberg, directs this documentary about Roy Cohn, who, as a young man, was partly responsible for that couple being wrongly convicted of espionage and executed. It starts with them, then shifts to Cohn, who’s shown wielding his influence and venom at first the Rosenbergs, then at Joe McCarthy’s side railing against accused Communists, before becoming an aggressive legal force whose clients included Studio 54, various mob bosses, a