A girl named Aparna dies in her house leaving her strands of hair as evidence. Forensic reports reveal that she died after consuming poison but it is not found anywhere at her residence. Then where did the poison come from and why did she have it?

The prime suspect of Aparna's death is her friend Smita's husband Gagan who works at a lab that produces the poison thallium nitrate and has been found missing but Gagan has something else to say about his wife.