The notorious House Unamerican Activities Committee starts calling witnesses. Their hearings with Tinseltown celebrities create a sensation and put Hollywood communists in the spotlight. Dalton Trumbo is among those summoned to Washington for hearings. Oona Chaplin explains why her grandfather Charlie was not called to appear despite his reputation as a leftist. Actress Katherine Hepburn takes a public stand against HUAC, publicly mocking its hearings at a Los Angeles rally.