The Castle of Otranto tells the story of Manfred, lord of the castle, and his family. His son, Conrad, is set to be married to princess Isabella, but dies on the day of the wedding. Manfred believes this event is the beginning of an ancient prophecy coming true - a prophecy telling of Manfred's downfall as lord of the castle. In an attempt to stop the prophecy, Manfred resolves to divorce his wife and marry Isabella. The princess escapes, but Manfred refuses to stop looking for her.
The Castle of Otranto was first published in 1764 and is regarded as the first gothic novel. The story merges medievalism and terror in a style that has endured ever since. The aesthetic of the book has shaped modern-day gothic books, films, art, music and the goth subculture. By combining fantastic situations with supposedly real people acting in a "natural" manner, Walpole created a new and distinct style of literary fiction, which has frequently been cited as a template for all subsequent gothic novels.