As orphaned Mary Yellan travels to Jamaica Inn to live with her aunt Patience and brutal uncle Joss, she discovers that the meeting point for a local smuggling gang is at the inn which upsets her. Mary keeps getting help from Joss's younger brother Jem.
Mary confides in the local vicar, Francis Davey after lying to the governor about the inn's involvement with smuggling. After she is rescued by Jem, Mary returns home to an unexpected surprise.
After Joss and Mary escape from the revenue officers, he and Patience decide to escape to Devon. As Mary finds herself in danger after her discovery, Jem must save her and reveal the head smuggler.