Raghava, a ghost-fearing man, living with his happy family consisting of his mother, brother, sister in law, and their daughter, set out to Coimbatore for a family function. In the function, the whole family, including Raghava's female cousins Priya, Kavya, and Divya, witness strange and scary incidents at their grandparents' house, as well as Raghava getting possessed. The subsequent events return to another character named Kaali.

Past: Kaali is a social worker, who runs an ashram that gives shelter and food to the poor, and also contributed to the studies of aspiring youths. One day, a politician named Bhavani, the brother of the minister named Shankar enters Kaali's ashram. He asks to keep a sum of black money worth ₹100 crore in his ashram. He tells that he should return ₹80 crore and keep ₹20 crore as a source of funding to his ashram.

However, Kaali refuses, which leads Bhavani to kill Kaali's handicapped innocents. Enraged, Kaali kills Bhavani and his henchmen and finally him. After learning this, Shankar and his assistant devises a plan to kill Kaali. When Rosie and Kaali take a ride on a bike, Shankar appoints two lorries and crushes them both. Rosie and Kaali die after watching the video of his ashram and his supporters getting destroyed in a fire accident orchestrated by Shankar.

Present: The possessed Raghava sets out to kill Shankar, but Shankar has already arranged exorcists to crush Kaali. Despite all this, Kaali surpasses the exorcists and kills Shankar, thus avenging his and Rosie's death. Kaali and Rosie safely return Raghava to his family and leave.