After the death of her mother, Mary Yellan is sent north to live with her aunt. It’s been many years since she’s seen Aunt Patience and Mary now finds her to be the wife of the landlord of Jamaica Inn. The place is notorious throughout Cornwall as being the seat of a wrecker gang — men who lure ships into the rocks, kill the crew, and steal their cargo. Patience is a broken woman with dog-like devotion to her husband Joss, despite his cruelty.
Mary confides in Joss’s estranged brother Jem and Francis Davey, vicar of nearby Altarnun. Jem is an unrepentant horse thief, but he prides himself that at least he’s no murderer. Davey is an albino, but his physical appearance isn’t the only thing strange about him. His cold and almost derisive demeanor is not in keeping with his profession.
The story comes to a head on Christmas Eve when Joss’s drunken carelessness catches up with him and his gang wrecks a ship too close to daybreak and has to scatter in chaos before being discovered. Joss plans to flee the country. Mary escapes the house and goes to Davey, but finding him not at home, continues to the squire to raise the alarm. When they arrive at Jamaica Inn, they find that Joss and Patience are both dead — stabbed in the back. It would seem that Joss was not the ringleader of the gang and that the actual boss had cut his loses.
But who is the boss? Mary, who’s been taken to the vicarage, isn’t long in suspense. Davey would seem not to be a very good Christian. In fact, he holds more faith in the old gods of the Druids. He abducts Mary and intends on taking her to Africa, but Jem has figured him out and leads a manhunt that ends in Davey’s death and Mary’s rescue.
Mary at first intends on going south to her home town, where she’s sure to find welcome by many friends, but at last throws caution to the wind and follows Jem wherever his lawless wanderings may take him.