Sesh Anka revolves around a girl Raina Roy Choudhury who gets framed in the murder case of Venkat Krishnaswamy. Criminal lawyer Pronoy Dasgupta and ACP Prithviraj is given the job to crack the case. Raina is the only daughter of business tycoon Ritabrata. Her mother committed suicide because of his father's illicit relation with his colleague Meenakshi. She starts taking drugs of the problems in her personal life. As a result her father stops her pocket money. To meet her expenses she is compelled to take up an assignment as an escort through a man called Anthony. Her client Krishnaswamy gets killed and she is framed. Raina's best friend Payal died in a car accident due to drugs. Payal's mother Amrita loves Raina as her own child and she takes it up to save her and appoints Pronoy. Pronoy with the help of detective John gets to know how Meenakshi was planning to ruin Ritabrata with the help of his business rival Rajiv Mitra. They had hired Anthony a renowned international smuggler and criminal to get her trapped. They become the suspects. But further investigations reveal that they didn't plan to trap Raina. After Pronoy solve the case.