The episode begins with Byomkesh Bakshi receiving a visit from an old friend, Mr. Sen, who is seeking his help in solving a puzzling case. Mr. Sen's son, Amit, has disappeared under mysterious circumstances, and the police are at a loss for leads.

Byomkesh, intrigued by the challenge, takes on the case and begins his investigation. He learns that Amit, a promising young engineer, was working on a top-secret project for the defense ministry. This raises suspicions that his disappearance may be linked to his work.

As Byomkesh delves deeper into Amit's life, he uncovers a web of secrets and hidden relationships. He discovers that Amit had been involved in a romantic affair with a married woman, Mrs. Dasgupta. This information leads Byomkesh to believe that the motive for Amit's disappearance may be related to jealousy or revenge.

Byomkesh's investigation takes him to a remote location where he suspects Amit is being held captive. With the help of his trusted companion Ajit, Byomkesh infiltrates the compound and discovers Amit alive but held against his will.

The mastermind behind Amit's abduction is revealed to be Mr. Dasgupta, Mrs. Dasgupta's husband, who was driven by rage and a desire to protect his family's reputation. Mr. Dasgupta confesses to his crime and releases Amit unharmed.

With Amit safe and the culprit brought to justice, Byomkesh and Ajit return to Calcutta, once again leaving their mark on the city's criminal landscape. Byomkesh's sharp intellect and unwavering pursuit of justice have once again triumphed over evil.