“The Mysteries of Udolpho” by Ann Ward Radcliffe — a free Project Gutenberg ebook, available to read as an EPUB on BookMarket.
Subjects: Castles -- Fiction; Gothic fiction; Guardian and ward -- Fiction; Horror tales; Inheritance and succession -- Fiction. Original source: https://www.gutenberg.org/ebooks/3268.
This ebook is in the public domain in the United States; the Project Gutenberg eBook license applies to the original text.