Agharnath is a tantric who has been practicing black magic for years. His aim is to attain immortality-he learns that he can do that only by sacrificing high own daughter who needs to be five years old at the time. He sets out on this task by abducting a college student called Chitra, whom he later puts under his spell. His joy knows no bounds when she gives birth to a daughter, Tara. However, the moment she does that, Chitra slips out of her trance and plans to escape. Agharnath foils her schemes as he imprisons her and their daughter in a cage deep inside the jungle where he lives.
Five years pass. Chitra learns about Agharnath’s intention of sacrificing Tara and hatches a plan wherein she tells him that he can have the girl if he sets Chitra free. As Agharnath lets Chitra prepare their daughter for the sacrifice, Chitra escapes. Agharnath sends his troop of evil spirits behind Chitra. She seeks refuge in a Kali temple where she leaves their daughter and runs so that the spirits are swayed away from the girl. However, Chitra dies in an accident. The temple where she abandoned her daughter is in the compound of a house belonging to Jagadish Chakraborty, Chitra’s maternal uncle.
On the other side, there are wedding festivities going on in the Chakraborty family. Jagadish Chakraborty has chosen a girl, Sreemoyee for his elder son Rudro. Chitra’s mother Basabi now lives with him and has become mentally deranged. The entire family except Basabi have gone to Sreemoyee’s village for the wedding. This is where Tulsi, Rudro’s mother, learns of Sreemoyee’s medical condition of not being able to conceive. She decides to stop the wedding but due to Rudro and Jagadish’s insistence it takes place. Throughout the wedding preparations and festivities, Sreemoyee keeps getting visions of Tara asking for her help. During the wedding, she feels a tug behind her, that of a young girl which she is convinced is coming from the temple at Chakraborty household. They all return immediately where Sreemoyee finds the girl and immediately grows attached. After resistance from Tulsi, Sreemoyee adopts Tara.
Soon, Agharnath comes to take back Tara but no one believes him. Unable to get Tara back, he then performs a ceremony where he creates a shapeshifter who takes the form of a beautiful woman called Nishi. Nishi soon seduces Palash, Rudro’s alcoholic brother, claims to be Tara’s mother and goes to the house. However, she cannot enter due to the presence of a divine force in the temple. As the story moves forward, Sreemoyee becomes the primary protector of the child and thus, is often at the receiving end of conspiracies hatched by Nishi. It is seen that while wielding her powers, Nishi’s hair attains a Medusa-like form (free flowing and long) and her pupils are unnaturally dilated (become black).
The journey continues with a good v/s evil approach with Tara at its centre, protected by Sreemoyee from Nishi and Agharnath’s evil schemes.