It is revealed that Prabhu had a twin brother named Kathir (also played by Dhanush), from whom he was separated in childhood due to Kathir's violent, psychopathic tendencies. Kathir was ostracized by their family and grew up to be a cold-blooded killer.

The film focuses on the theme of "déjà vu" and the contrast between the two brothers, one representing light/family and the other representing darkness/trauma.

The plot culminates in a violent confrontation between the two brothers, Prabhu and Kathir, as Prabhu fights to save his family from his twin's psychopathic clutches.