Summary Calcutta, 1964. Bhupesh Chatterjee (Mahan Swadesh) lives in the same building as Byomkesh. Byomkesh is away to Cuttack & Bhupesh invites Ajit to be a bridge player in his group. Bhupesh works for an insurance firm and travels a lot. The other 2 players are Ramchander (Ashok Tande) and Banmali (Ashok Mishra), who also live in the same building. One night, while coming down to meet the 3 players, Ajit hears a loud noise. He reaches Bhupesh's room, who says that the noise came from the room below, and he saw a man running away from the building. The room below belongs to Natwarlal Naskar. They find Natwarlal shot dead in his room with a pistol on the window ledge. It looks like the killer shot Natwar from window & then ran away. The killer was seen wearing a red shawl. Bhupesh claims that he saw the person run away. Ramchander and Banmali are with him at that time.

Shortly thereafter the manager Shiv (Robin Gupta) of the building comes in wearing a red shawl. Shiv claims that he was outside on some personal work. Ajit calls the police. Shiv tells police that he has been managing the building for 25 years. Natwar came there 3 years ago and only knew Ramchander and Banmali in the building. Bhupesh is a widower, without kids. Got transferred to Calcutta 2 months ago and loves to play bridge. That's how he came to know Ajit, Ramchander and Banmali. Bhupesh heard a loud noise and went to his window on the 2nd floor, where he saw a man wearing a red shawl running away.

Ramchander's family was killed in Dhaka during partition & he came to live in Calcutta. he knew Natwar from Dhaka. Banmali also has the same story. He and Ram used to work for an MNC in Dhaka & both now work for a bank in Calcutta for last 4 years. Hari (Prem Dutta) is a servant of the mess & reports that on the evening of Natwar's murder he had heard an argument going on in Natwar's room. As the door was closed, he could not see who was inside. Byomkesh returns to meet everyone. He finds that Bhupesh had also lost his young son in the Dhaka riots & plays bridge to distract himself from grief. His wife died soon after the boy died, due to grief. Ramchander & Banmali claim that they only had peripheral acquaintance with Natwar in Dhaka as well. While Bhupesh says he never saw Natwar alive.

Byomkesh sees Natwar's belongings which has a Dhaka court deed declaring that 2 brothers Rasbihari and Banbihari, employed as treasurer for a MNC in Dhaka, were sentenced to 3 years in jail for fraud. Byomkesh concludes that Natwar was a blackmailer. Ramchander & Banmali are Rasbihari and Banbihari respectively. Natwar was in the business of blackmailing. He planned to blackmail Ras & Banbihari when they got released from jail. But then the partition happened & Natwar came to Calcutta and lived poorly. By luck he found that Rasbihari and Banbihari have come to live in the same building as him. Natwar started blackmailing them for Rs 80 per month. The brothers admit this but say that they did not kill Natwar.

Byomkesh says that a gun shot sound is not like a bomb. It is sharp. Byomkesh then reveals that Bhupesh is the killer. He entered Natwar's room in the evening before the bridge game. He killed Natwar with a muzzled gun & left the gun on the window. Then, when Ram & Banmali came to his room, he went to his own window, threw a loud cracker down the window, and screamed that a man is running away. In the heat of the moment, Ram & Banmali agreed with him.

Bhupesh agrees & reveals that Natwar had kidnapped his son & asked for Rs 10,000 as ransom. Bhupesh gave him everything he had, but his son never came back. His wife also died from the shock. Then, when Bhupesh got transferred to Calcutta, he saw Natwar & started living in the same building & killed him at the first opportunity. Byomkesh promises to protect Bhupesh, but still encourages him to go to police & tell the truth.

• Adventure
• Crime
• Mystery
• Thriller