The somewhat melodramic story of Ernani, set in 16th century Spain, revolves around four main characters. At the centre of the action is the beautiful young Elvira, and vying for her love are her uncle (and guardian) Don Ruy Gómez de Silva, an old Spanish grandee; Don Carlo, the King of Spain; and Ernani - whom Elvira loves - and who has become a dashing bandit, having lost both his title and his wealth during a civil war.
Ernani is under an obligation to de Silva, for protecting him from the king, having sworn to take his own life should de Silva demand it, and just when a happy ending appears to be in sight, honour takes centre stage, with tragic results for Elvira and the man she loves.