Her mother's dying request takes Mary Yellan on a sad journey across the bleak moorland of Cornwall to reach Jamaica Inn, the home of her Aunt Patience. With the coachman's warning echoing in her memory, Mary arrives at a dismal place to find Patience a changed woman, cowering from her overbearing husband, Joss Merlyn.

Affected by the Inn's brooding power, Mary is thwarted in her attention to reform her aunt, and unwillingly drawn into the dark deeds of Joss and his accomplices. And, as she struggles with events beyond her control, Mary is further thrown by her feelings for a man she dare not trust....