The play is set in 1893. Zastrozzi, the master criminal of all Europe and a self-proclaimed atheist, like the character in the 1810 novel and Shelley himself, has focused for nearly three years on the pursuit of revenge against the murderer of his mother, the whimsical, unconstant, and delusively God-obsessed artiste Verezzi. In the Shelley novel, Zastrozzi's mother Olivia is seduced and impregnated by Verezzi's father when she was fifteen, Zastrozzi is the illegitimate son, Verezzi is his half-brother and Olivia dies at thirty in poverty and abandoned, demanding that Zastrozzi avenge her. In both the novel and the play, Zastrozzi, with the help of his heartless protégé Bernardo and his sometimes lover the seductress Matilda, chases Verezzi to a small town in the Italian countryside and engineers an elaborate plot to destroy his enemy. But while Verezzi may be an easy target, his tutor Victor, a former priest, presents a much more difficult challenge for Zastrozzi.