"The Castle of Otranto" by Horace Walpole is a Gothic novel, often considered the first of its kind. The story begins when the son of Manfred, the ruler of Otranto, is mysteriously killed just before his wedding. In his desperation to secure his lineage, Manfred sets out to marry his late son's betrothed, leading to a series of supernatural occurrences and ethical dilemmas. With its haunted castle setting, doomed nobility, and chilling atmosphere, the book established many of the themes and settings that would define the Gothic genre.