The game takes place in the dark fantasy world of the Diablo series twenty years after the events of Diablo II. Deckard Cain and his niece Leah are in the Tristram Cathedral investigating ancient texts regarding an ominous prophecy. Suddenly, a mysterious star falling from the sky strikes the Cathedral, creating a deep crater into which Deckard Cain disappears.

The game takes place in the dark fantasy world of the Diablo series twenty years after the events of Diablo II. Deckard Cain and his niece Leah are in the Tristram Cathedral investigating ancient texts regarding an ominous prophecy. Suddenly, a mysterious star falling from the sky strikes the Cathedral, creating a deep crater into which Deckard Cain disappears.