Lord Ruthven is such a Vampire. He victimizes young maidens in particular. His soul is sold to Satan, but the demons have granted him a respite of a year, on condition of his bringing them three brides young and pure. His first victim is Janthe, daughter of Sir John Berkley. She loves the monster and together they disappear into a cavern. Her father assembles followers and goes in search of her. They hear dreadful waitings, followed by mocking laughter proceeding from the ill-fated Vampire, and entering they find Janthe lifeless. The despairing father stabs Ruthven, who wounded to death knows that he cannot survive but by drawing life from the rays of the moon, which shines on the mountains. Unable to move, he is saved by Edgar Aubry, a relative to the Laird of Davenant, who accidentally comes to the spot.
Lord Ruthven, after having received a promise of secrecy from Aubry, tells him who he is and implores him to carry him to the hills as the last favor to a dying man.
Aubry complies with the Vampire's request and then hastily flies from the spot. Ruthven revives and follows him, in order to win the love of Malwina, daughter of the Laird of Davenant and Aubry's betrothed.
His respite now waxing short, he tries at the same time to gain the affections of John Perth's the steward's daughter Emma.
Malwina meanwhile greets her beloved Aubry, who has returned after a long absence. Both are full of joy, when Malwina's father enters to announce to his daughter her future husband, whom he has chosen in the person of the Earl of Marsden. Great is Malwina's sorrow, and she now for the first time dares to tell her father, that her heart has already spoken and to present Aubry to him. The Laird's pride however does not allow him to retract his word, and when the Earl of Marsden arrives, he presents him to his daughter. In the supposed Earl, Aubry at once recognizes Lord Ruthven, but the villain stoutly denies his identity, giving Lord Ruthven out as a brother, who has been travelling for a long time. Aubry however recognizes the Vampire by a scar on his hand, but he is bound to secrecy by his oath, and so Ruthven triumphs, having the Laird of Davenant's promise that he will be betrothed before midnight to Malwina, as he declares that he is bound to depart for Madrid the following morning as Ambassador.
In the second act all are drinking and frolicking on the green, where the bridal is to take place.
Emma awaits her lover George Dibdin, who is in Davenant's service. While she sings the ghastly romance of the Vampire, Lord Ruthven approaches, and by his sweet flattery and promise to help the lovers, he easily causes the simple maiden to grant him a kiss in token of her gratitude. In giving this kiss she is forfeited to the Evil One. George, who has seen all, is very jealous, though Emma tells him that the future son-in-law of the Laird of Davenant will make him his steward.
Meanwhile Aubry vainly tries to make Ruthven renounce Malwina. Ruthven threatens that Aubry himself will be condemned to be a Vampire, if he breaks his oath, and depicts in glowing colors the torments of a spirit so cursed. While Aubry hesitates as to what he shall do, Ruthven once more approaches Emma and succeeds in winning her consent to follow him to his den, where he murders her.
In the last scene Malwina, unable any longer to resist her father's will, has consented to the hateful marriage. Ruthven has kept away rather long and comes very late to his wedding. Aubry implores them to wait for the coming day, but in vain. Then he forgets his own danger and only sees that of his beloved, and when Ruthven is leading the bride to the altar, he loudly proclaims Ruthven to be a Vampire. At this moment a thunder-peal is heard and a flash of lightning destroys Ruthven, whose time of respite has ended at midnight. The old Laird, witnessing Heaven's punishment, repents his error and gladly gives Malwina to her lover, while all praise the Almighty, who has turned evil into good.