The sudden, inexplicable death of a young nobleman on his wedding day triggers a series of supernatural events that threaten the usurping ruler of Otranto. Manfred, the lord of the castle, attempts to secure his lineage and power through forced marriage and political maneuvering while facing the encroaching weight of an ancient curse. He must contend with mysterious omens, spectral appearances, and the resistance of those trapped within his fortress. The narrative unfolds through a dramatic, theatrical framework that emphasizes the tension between aristocratic duty and the intrusion of the uncanny.

Readers and critics frequently identify this work as the foundational text of the Gothic genre, noting its influence on subsequent horror literature. Discussion often centers on the deliberate blend of archaic romance elements with modern narrative pacing, which creates a distinct atmosphere of dread. While some modern readers find the prose style and character motivations to be highly stylized or melodramatic, others appreciate the historical significance of the text's structural innovations. The effectiveness of the castle as a central, almost sentient character remains a primary point of interest for those examining the origins of atmospheric fiction.