Sevanthi, ancient faith clashes devastatingly with modern skepticism within the remote, mist-shrouded village of Kadambam. Here, a people live in sacred harmony with a mountain they revered as a goddess. Their tranquil existence is irrevocably altered when an orphaned girl, Sevanthi, becomes the conduit for the mountain's raw and terrifying power.

Far away, the celebrated but profoundly cynical author, Parthiban, haunted by a personal tragedy born of blind faith, learns of Kadambam’s living goddess. Convinced their belief is a dangerous illusion, he embarks on a cruel crusade to expose it as a fraud. His meticulously planned experiment to shatter their faith inadvertently unleashes a chain of events—betrayal, murder, and divine retribution—that will prove the goddess is terrifyingly real. Sevanthi is a cosmic horror that questions the boundaries of belief and the perilous consequences of human arrogance.