Ichhadhari Nagin: Part 1

A group of archaelogical students go on a treasure hunt. They kill a serpent that was guarding the treasure inspite of one of the group members being against the idea. As they were leaving the excavation site, they meet a sorcerer, who warns them that they made a mistake. Later that night, Koel, one of the members from the team gets killed from a snake bite. Everyone suspect Aabha for the death as she was against the idea of killing the snake. When Aabha's boyfriend reaches out for K.D.Pathak for help, a special researcher visits Pathak's office. How will KD solve this case? Is the researcher involved in the killings?