In 17th-century Scotland, a bitter feud rages between the Ashton and Ravenswood families. Lucia Ashton and Edgardo of Ravenswood are secretly in love and pledge their eternal devotion before Edgardo leaves for a political mission in France. Lucia’s ambitious brother, Enrico, facing political ruin, sees a strategic marriage for his sister as his only salvation. He intercepts Edgardo’s letters to Lucia and forges a letter to convince her that her beloved has been unfaithful.

Heartbroken and pressured by her family and the chaplain Raimondo, the fragile Lucia reluctantly agrees to marry the influential Lord Arturo Bucklaw. The wedding contract is signed just as Edgardo dramatically returns, sees the proof of what he believes is Lucia’s betrayal, and curses her.

The shock is too much for Lucia’s delicate mind. On her wedding night, she descends into madness, murders her new husband, and appears before the horrified guests in a bloodstained nightgown. In a haunting, dreamlike state, she imagines her wedding to Edgardo before collapsing. Upon learning of Lucia’s death, the despairing Edgardo, who has decided to die in a duel with Enrico, takes his own life with a dagger, longing to be reunited with his beloved in heaven.