Undying begins in 1923 after WWI veteran Patrick Galloway receives a letter from an old friend of his, Jeremiah Covenant. In it is a request to go to the Covenant Manor and investigate some strange happenings there. Upon further investigation, he finds that Jeremiah's dead siblings have returned as spirits and are causing the unusual occurences. He embarks on a mission to attempt to stop the siblings which takes him to various locations across the Covenant Estate. As the story progresses, Galloway finds that the current generation of Covenants engaged in a ritual which they thought was a game in childhood. This lead to a curse being placed upon the family. The curse is the Undying King, which wishes to manifest itself on Earth. This is all helped by a pagan priest, Otto Keisinger. At the climax of the game, Galloway finds that Jeremiah has betrayed him, and is beheaded for his treachery.