M.G. Lewis 
The Monk [EPUB ebook] 

Newly arrived in Madrid, Leonella and her niece Antonia visit a church to hear the sermon of a celebrated priest, Ambrosio, and while waiting tell their story to two young men, Don Lorenzo and Don Christoval. Antonia’s Grandfather is the Marquis de las Cisternas, who was unhappy with his son’s marriage, causing her parents to flee, leaving their young son behind only to be told a month later he has died. Leonella has come to Madrid to convince the Marquis’ son, Raymond de las Cisternas, to resume their pension, which has been cut off. As the story is told, Lorenzo falls in love with Antonia. The mysterious priest, who was left at the abbey as a child, delivers the sermon, and Antonia is fascinated with him. Lorenzo vows to win the hand of Antonia, but must first visit his sister Agnes, who is a nun at the nearby abbey. Having fallen asleep in the church, he awakens to find someone delivering a letter for his sister from Raymond de las Cisternas. On the way home, a gypsy warns Antonia that she is about to die, killed by someone who appears to be honorable…