Read "The Mysteries of Udolpho" by Radcliffe, Ann Ward for free. A classic public domain work covering castles -- fiction, gothic fiction, guardian and ward -- fiction. Available in full text from Project Gutenberg.
Castles -- Fiction
Gothic fiction
Guardian and ward -- Fiction
Horror tales
Inheritance and succession -- Fiction
Italy -- Fiction
Orphans -- Fiction
Young women -- Fiction
This book is in the public domain. Free to read and download from Project Gutenberg.