Summary Calcutta, 1960. Mrigen (Sunil Chauhan), Arvind (Babloo Mukherjee), Madhumoy (Aditya Srivastav) and Manish are bridge players at a Calcutta club. Pran Hari (Sumant Mastakar) is a brilliant bridge player and is new to the city and to the club. Pran makes friends with all & invites them to his house for gambling (which is illegal in public places). At Pran's house he has a long serving servant Mohini (Dolon Roy), who is good looking & the young boys are infatuated with her. Arvind starts chatting up Mohini, while Pran keeps winning big. One day the 4 friends see that Pran is cheating at the game, while keeping them busy on Mohini.

The friends are furious & want to teach Pran a lesson. They go back to his house in a taxi. Arvind goes to his room but finds it locked. He returns a few moments later with his friends. This time the door is open & Pran is found dead inside. The 4 friends run away in the same taxi they arrived. Mohini was cooking dinner in the kitchen and didn't see anything. At night, she found Pran's body and got the message to the police.

Byomkesh investigates. He finds Rs 10,000 in the closet in Pran's room and Rs 1.5 L in his bank account. Arvind's elder brother had offered a bribe to the police inspector to shut the case. Arvind used to visit Mohini in Pran's absence to woo her, but she resisted his charms and bribes. Mohini is married, but her husband ran away. She has decided to return to her village as soon as the investigation is complete. Pran died from a blow to his head & from the front. Pran's room had 2 entrances, one from within the house, and one from outside.

Looking at Pran's ledgers, Byomkesh figures that Pran had an unexplained income of Rs 70 per month and figures that perhaps he was blackmailing someone. Mrigen and Madhumay are hostile to Byomkesh. But Arvind and Manish are friendly. Arvind admits that he paid Rs 2000 to Pran Hari, who was acting as Mohini's pimp, to spend time with Mohini. But all 4 friends deny going to Pran's house on the night of his murder. The police trace the taxi driver who admits to dropping the 4 friends a 100 ft from Pran's house & then picking them up 2 hrs later.

Byomkesh meets Mohini again, but she remains elusive in her answers. A few hrs later, the taxi driver picks up Mohini & runs away with her. Byomkesh gets Pran Hari's locker in the bank opened, which has a document that says that Bhuvneshwar Das (Prem Dutt) (the taxi driver) has mortgaged his taxi to Pran for Rs 2500, and in exchange Pran would use the taxi daily for his office commute in exchange of payment of Rs 70 per month.

Byomkesh reveals that Mohini was Bhuvneshwar's wife. They stayed together in Cuttak. But Bhuvneshwar started working as truck driver for army & left Cuttak. So, Mohini started working for Pran. Pran wanted to use Mohini as a honey trap to get the 4 young men to gamble with him. But Mohini was not that way.

Bhuvneshwar had come back from army & wanted money to buy a taxi, which Pran gave to him, when Mohini approached Pran. Pran's plan was to keep both Bhuvaneshwar & Mohini under his control. But then Pran made a deal to pimp Mohini to Arvind for Rs 2000. When Bhuvaneshwar found out, he was enraged.

It was sheer luck that the 4 boys hired Bhuvaneshwar's taxi to go to Pran Hari's house that night. Bhuvaneshwar heard their conspiracy & decided to kill Pran that night, by entering his room through the back door & hitting Pran on his head. Before escaping, Bhuvaneshwar opened the front door of the room (which is why it was open when Arvind returned to the room with his friends). Mohini was not aware of anything as she was in the kitchen cooking dinner. When she discovered Pran's body, she closed the 2nd door, which opened to the outside of the house.

Bhuvneshwar and Mohini escape town.

• Adventure
• Crime
• Mystery
• Thriller