Lord Henry Ashton of Lammermoor is dominant over his enemy, Edgardo of Ravenswood, after a battle. Edgardo and Lucia, Ashton`s sister, have fallen madly in love and she accepts his hand in marriage. But, Ashton has arranged for Lucia to wed Lord Aturo Bucklaw, and this arrangement will make them rich. Edgardo has to leave town for a while. While he is gone, Ashton forges a letter from Edgardo to Lucia saying that he has found another lover. Ashton gives the letter to Lucia and she is devastated. Lucia agrees to marry Lord Bucklaw.

Soon, Edgardo returns and challenges Bucklaw, but it is too late, the marriage document has been signed. Edgardo sees the Lucia`s signature and curses her. Lucia goes mad and murders Lord Bucklaw.