Feluda, his cousin Topshe and the thriller writer Jatayu visit Benaras during the pujas. There they meet a Bengali family. Upon hearing that Feluda is a private investigator, the Ghosal family head entrusts him with the task of finding out the thief of the attempted theft that took place in their house. Meanwhile, the arrival of a saint by the name of ‘Machhli Baba’ in Benaras quivers the excitement of the local people.
A very valuable property of the Ghosals, a golden Ganesh statue, about three inch height, was the target of the thief. On the other hand, Maganlal Meghraj, a wealthy Marwari businessman, had his eyes on the Ganesh for a very long time. He comes to know about the involvement of Feluda in this case. He invites Feluda, Topshe and Jatayu to his house and offers Feluda Rs.2000 so that he leaves this case. Feluda refuses, which angers Maganlal, and he sets up a knife throwing show, using Jatayu as the bait (much to the viewer’s amusement). After the thrilling adventures in Maganlal’s house, Feluda takes a vow – either he will avenge Jatayu’s harassment, or quit being a sleuth.
Although warned by Maganlal, Feluda did not lose interest in the case, and deduces that Machhli Baba is actually a fraud working for Maganlal. A member of the Ghosal family, Bikash, was also bribed by Maganlal to steal the Ganesh and hand it over to him. Feluda gets hold of Bikash and makes him confess his involvement in the theft. But Bikash states that when he went to steal the Ganesh, it was not there. Several questions arise in Feluda’s mind. Where is the Ganesh, then? Why the innocent idol-maker of the Ghosals Shashi Babu was murdered brutally? What plan did the Ghosal family head hatch upon with his grandson to save the Ganesh?