After a prologue which shows Eve giving the apple to Adam, Mary Magdalene, the feast of Belshazzar, the ancestors of the "vampire" being tried for witchcraft in 1692 and an incident in 1840, the modern story begins. To escape the clutches of the law, vampire Grace Penrose flees New York to the little hotel in the mountains owned by the mother of her last victim, Dan Morgan. En route, her sleigh overturns and she is rescued by John Winthrop, a young married man who is living happily in the mountains with his wife and child. Grace attempts to ensnare him in her spell as John struggles to remain aloof. Arriving at the hotel, she is met by Morgan, who doesn't dare reveal his affair with the adventuress. Continuing her campaign to lure John, Grace eventually succeeds, and he informs his wife that he is leaving her. After pleading with both her husband and Grace, Mrs. Winthrop tells her trouble to Morgan's mother. Morgan finally confesses to his mother, and produces a photo of Grace endorsed with a message of undying love. With the photo as proof, they rouse the townspeople, who tar and feather the adventuress, after which John returns, chagrined, to his wife.