Summary 1957. Manimoy (Bunty Behl) & his father Rasmoy (R.S. Chopra) are in the jewelry business. They have made an expensive necklace for a customer in Delhi, worth Rs 60,000. The customer has already paid an advance of Rs 40,000 and Mani is to take the item to Delhi for delivery and get the remaining 20,000. Mani's wife Uma (Indrani Dutta) loves the necklace & wants a similar jewel for herself. She is not happy that Mani is going to Delhi alone. Rasmoy keeps the necklace in his safekeeping for the night, in his study drawer & has Mani's wife sew the jewel into an old cloth piece to conceal it.

Mani is in habit of gambling at his club every night. Rasmoy suffers from joint pain and has Bhola (Samir Jani), the house servant, to massage him every day. That night also Bhola comes into Rasmoy's room and massages his legs, as Rasmoy falls to sleep. Mani comes back around mid-night & finds a man standing near the entrance to the house. His wife also saw this man running across the courtyard (as she looked outside waiting for Mani to come back home), but it was dark, so no face was visible. The man ran away after seeing Mani. Mani goes to Rasmoy's room to see the necklace missing.

Rasmoy summons Byomkesh for help & explains that he has 5 jewelry shops & a business worth Rs 30 L per month. All his employees in the shop are old timers and above suspicion. His customer in this instance was Ramdas Chowksi, who himself is a jeweler in Delhi. When the necklace was ready, it was stored in the shop locker and only brought home the day before Mani was supposed to take it to Delhi for delivery. His wife has gone for religious pilgrimage with his younger son. Uma handles the entire house all by herself. When the police came, they searched the entire house, but could not find the necklace. Rasmoy says that only Mani, Uma and Bhola entered the room in the last 24 hours.

Byomkesh speaks to Bhola who says they are 3 brothers and 2 sisters, who are also in Calcutta. Bhola has been working for Rasmoy for 3 years now. The elder brother is a postman and the younger works in the Municipal corporation. Bhola says that he went outside the house around midnight for fresh air. He ran inside when he saw Mani returning to the house.

Byomkesh questions Mani's wife and finds that she comes from an ordinary household. She is in a family of 4 sisters and 2 brothers & sends money home to support them. She has infrequent contacts with her family. She admits to seeing Rasmoy hiding the jewel but says she didn't enter the hiding place after putting Rasmoy to bed. She did visit her father after the theft for an hour. She admits to having the desire to posses the necklace. Mani also tells Byomkesh that Uma wanted a similar necklace and she asked him for it the previous night, before it was stolen. Byomkesh alleges that Mani entered the house, went straight to the study drawer, and took the necklace from there. Normally, Mani could not afford a Rs 60,000 necklace, so stealing it was the only way to fulfill his wife's wish. He also could have lost money in gambling.

Then Byomkesh sees Uma posting a letter in a post box just outside the house. Byomkesh finally figures that it was Bhola who stole the necklace & put it inside the post-box outside the house. Bhola's brother was a postman & the plan was for the brother to pick up the necklace when the matter cooled down.

• Adventure
• Crime
• Mystery
• Thriller