In a heady tale of revenge and obsession, the outlaw Zastrozzi, assisted by courtesan, Matilda, abducts his half-brother, Verezzi, and torments him into believing his lover, Julia, has been murdered. His campaign of vicious psychological abuse signals a grisly bloodbath of greed, envy, betrayal, retribution, and eternal damnation.
Verezzi is abducted by Ugo and Bernardo, two henchmen working for the mysterious outlaw Zastrozzi. He is able to escape.
Verezzi is befriended by Claudine. Zastrozzi and Matilda conspire to manipulate Verezzi. They keep him under their control.
Matilda informs Verezzi that Julia is dead. He then succumbs to her advances.
Verezzi discovers that Julia is alive. He kills himself because he regards his romance with Matilda as a betrayal. Outraged, Matilda kills Julia.