Alicia Harlow, a dedicated traveling nurse, accepts an assignment in the isolated town of Blackville, unaware of the darkness lurking beneath its quaint facade. What begins as a routine medical placement quickly spirals into a nightmare when Alicia discovers Blackville is controlled by a sinister cult devoted to an ancient evil deity.
The townspeople, bound by generations of worship, perform horrific rituals to appease their dark god. As Alicia uncovers the truth, she becomes their next intended sacrifice. In a desperate escape attempt, she is wounded and unknowingly contaminated with the malevolent god's blood.
Though Alicia manages to flee Blackville, she carries something insidious within her. The deity's blood acts as a contagion, spreading wherever she travels. Those infected undergo terrifying transformations into monstrous creatures no longer fully human.
As the infection spreads across continents, an apocalyptic phenomenon begins: landmasses slowly sink beneath rising waters, as if primordial forces are reclaiming the world itself. Caught between guilt over her unwitting role in this catastrophe, Alicia must confront the horrifying reality that maybe she can't do anything to stop it.