A door-to-door masseuse, Kaali finds her life turning upside down when her son, Sunny, meets with an accident and her husband, Tanmay, gets arrested for the murder of a drug dealer.
Kaali desperately seeks a way to arrange money for Sunny's operation. Her only way out is to sell the drugs that Tanmay had hidden in the house.
Kaali gives in to selling drugs for money and steals a consignment in her desperation to save Sunny. Special Branch Officer, Aniket Bose, smells something fishy after interrogating Tanmay.
Kaali tries to sell the stolen consignment while getting into a bad blood with the drug mafia. Her past lover, Officer Aniket Bose resurfaces in her life, through the ongoing police investigation involving her husband.
Kaali gets entangled in a web of violence and abuse while on the run from the drug mafia. Aniket's suspicion strengthens as he uncannily crosses paths with Kaali at odd places.
Kaali is tricked by her landlord into the hands of the drug mafia. She manages to fool them and seeks refuge from the police, not knowing their deep-rooted corruption.
Despite Aniket's warnings, Kaali agrees to lead the police into the drug lord, Dilip's den. Kaali is dumbstruck when she learns of OC Mitra's true intentions.
Aniket takes Kaali into custody after a bloodbath with the drug mafia but lets her out one last time to pay for Sunny's operation. Amidst this, Kaali realises that Kolkata has been shackled by the international drug mafia.