Arnab a typical Bengali man is making his way back to Kolkata after meeting a girl, the arranged marriage way. He and his parents liked the girl and marriage is on the cards. But suddenly, there is an accident. His car hits an old woman. They take her to the hospital. But she dies on the way.

This is how Arnab meets Rukhsana. The daughter of the old woman is a mysterious girl who lives in a hut outside a village with a few dogs and whose mother always shackled her to a pole with metal chains before she left house.

The news of her mother`s death spreads. A Professor from Bangladesh immediately flies to India and is now out to get Rukhsana. He gathers a mob and attacks Rukhsana with the motive to kill her.

But she escapes and makes her way to Arnab`s house. She barely knows the place, and the apartment is locked from inside, yet when Arnab awakes that night, he finds her in his room, trembling with fear. She refuses to leave him.

Arnab has no option but to keep her. Slowly, he starts enjoying her company. She is strange and mysterious. She doesn`t have any idea about modern day living. She has never used a TV, a phone or a refrigerator ever. She is very careful about her nails and cuts her nails daily and when she can`t find the nail cutter, she gets paranoid and tries to cut them with the kitchen knife. Fear permeates her very being. A scary face haunts her dreams. A face that whispers her name...

Slowly, the friendship turns into love. Though Arnab tries to resist himself, he feels an unflinching attraction towards Ruksana`s beauty and innocence. One night all barriers break apart: they make love so passionately that world seems to come to a halt.

Then, the events take a twist when the Professor, who was meanwhile incessantly searching for Rukhsana, finds her at Arnab`s place. He meets Arnab and tells him that Rukhsana is the daughter of the devil himself. She has venom inside her. Venom that needs to be taken out every three weeks. Venom that consumes animals, birds and sometimes people. The love story then moves towards a horrifying end...