In Roman-occupied Gaul, the Druid high priestess Norma has secretly broken her sacred vows of chastity by bearing two children with the Roman proconsul Pollione. Her secret world shatters when Pollione abandons her for Adalgisa, a young temple novice. Heartbroken and furious, Norma considers killing her own children to punish him but is stopped by maternal love. When Adalgisa learns of the betrayal, she refuses Pollione and urges him to return to Norma. However, Pollione attempts to abduct Adalgisa from the temple. Norma discovers the attempt and calls the Gauls to war against Rome. When Pollione is captured, Norma offers him a final choice: give up Adalgisa or die. When he refuses, Norma publicly confesses her own guilt to the Druids. Touched by her supreme sacrifice, Pollione’s love is rekindled, and he joins Norma on the sacrificial pyre.