In the early 1800s, Mary Yellan's life is changed after her father is murdered by shipwreckers. When her mother dies of a broken heart not long afterwards, Mary is forced to go live with her Aunt Patience at her inn on Bodmin Moor. It's there that she discovers her slightly mad Uncle Joss is the wreckers' ringleader and that Jamaica Inn is their headquarters. Mary is determined to bring Joss and his gang to justice and calls upon Joss' younger brother Jem to help.