Clive Barker's Undying is a horror first-person shooter video game developed by DreamWorks Interactive and published by EA Games. The game was produced by acclaimed horror writer Clive Barker. He also provided the voice of Ambrose Covenant, a character in the game.
Undying follows the adventures of 1920s Irish paranormal adventurer Patrick Galloway as he investigates the mysterious occult happenings at the estate of his friend Jeremiah Covenant.
In 1923, World War I veteran Patrick Galloway receives an urgent letter from his friend Jeremiah Covenant. Covenant, well aware of Galloway's reputation for dealing with occult matters, is in failing health and raves about a curse that has destroyed his entire family. Galloway travels to the Covenant estate on the coast of Ireland to visit his friend, who relates an outlandish tale of supernatural terrors.
Jeremiah Covenant is the eldest of five children, his siblings being, from eldest to youngest, twins Bethany and Aaron, Ambrose, and Lizbeth. As children, the Covenants found a strange occult book in their father's library and performed a ritual found within at an ancient set of standing stones located on an island on their family's extensive estate. This seemingly childish game, however, brought the wrath of evil forces upon the family. After reaching adulthood, the Covenants fell one by one into madness and then death, eventually leaving Jeremiah as the only survivor. The power of the curse, however, has reanimated his fallen siblings as monsters of pure evil; they have been haunting Jeremiah and he fears that he will soon follow where they have gone.
Galloway decides to honor his friend's wishes by trying to stop whatever was set in motion long ago at the ancient stones where the ritual was performed. Through the Covenants' journals and Galloway's own memories, the player learns more about the nature of the curse and the creature behind it: the Undying King, a powerful demonic presence threatening to destroy the reality we inhabit. He also receives a vision of a group of priests burying a Celtic king alive as part of a ritual in ancient times.
While attempting to prevent the Undying King from entering our world, Patrick must face off against the four undead Covenant siblings as well as Count Otto Keisinger, an evil rival who simply wants to gain power from the demonic forces.
As Patrick begins to unravel the mysteries of the Covenant family, he finds himself traveling throughout both time and space, traversing both the ancient past and other dimensions entirely. During his journey to the past, he arrives in a monastery where the only weapon that can permanently kill the Covenant siblings is located, namely the Scythe of the Celts. However, due to the presence of the Scythe in the monastery, all of the monks have fallen under its influence, turning them from benevolent worshippers of faith into murderous psychopaths.
After retrieving the Scythe, Patrick first disposes of Lizbeth in the Covenant family catacombs. Having tossed her head of the cliff, he arrives back at the mansion in time to speak with Jeremiah, but Ambrose interrupts their meeting. Demanding the Gel'ziabar Stone that Patrick carries in exchange for Jeremiah's life, Ambrose still beheads his sibling after he has gotten it, turning himself into a hulking ogre-like monster. Patrick manages to kill Ambrose in revenge. His next step is then to go after Keisinger, and after a taxing battle Patrick manages to defeat his rival. Keisinger's death liberates the inhabitants of the magical dimension of Oneiros that Keisinger had enslaved to his will.
Next, he searches for the body of Aaron, whose intangible, but dangerous ghost is haunting the estate and has been annoying and impeding Patrick on several occasions. He discovers it in a private torture chamber where Bethany had secretly imprisoned and horrifically tortured her hated brother to death, and destroys his undead form. Patrick finally confronts the last of the evil Covenant siblings, Bethany, after she traps him in the magical primeval dimension Eternal Autumn, only to find himself suddenly returned to the island where it had all begun all those years ago, and finds himself facing an unexpected enemy - Jeremiah himself.
Rather than being a passive, remorseful observer of the tragic events, Jeremiah had in fact been just as corrupted as his siblings, having died and been resurrected during the war, and had just been using his old friend to get rid of his more powerful siblings so he could take Patrick's Gel'ziabar Stone and use it to siphon the power of the Undying King into himself, allowing Jeremiah to remake the world as he saw fit. Furious at his friend's treachery, Patrick beheads Jeremiah, but this proves to be a mistake, as with the last Covenant slain, the seal is broken, and the Undying King is released. The ground bursts open, releasing the mummified remains of the Celtic warrior who had been used to seal away the Undying King by the original druids, and the warrior quickly crumbles to dust. Then, the King itself, a hideous, insectoid monstrosity, finally breaches the walls to our reality.
After a long, difficult battle, Patrick is able to destroy the King, but as he leaves the island in a daze, a man he recognizes (and who he says cannot possibly be there) steals his Gel'ziabar Stone and claims that he isn't done with Patrick yet. A sequel hook is added by a mention that after researching the brotherhood of monks, Patrick learns that they had monasteries at similar sites all over the world, and he realizes that this is just one of many coming trials.