Storyline : Sona da in with Abir and Jhinuk embarks on his new adventure, a quest that will take them to the legendary Durgeshgor. The journey reveals that the Debroy family, the erstwhile zamindars in their princely mansion hold the key to a presumed rumor of a treasure connected with Plassey. With an amazing vibrant backdrop of Durga Puja in the princely Debroy mansion where the trio is invited for the occasion, one after the other clues are revealed testing Sona da’s wit and grit one more time leading towards the discovery of one of greatest treasures Bengal has ever witnessed.
Professor Subarna Sen, aka Sona Da, a professor of history, along with Abir and Jhinuk decide to visit one of Sona da’s student’s ancestral mansion at Durgeshgor. The great grandfather of this student was an erstwhile zamindar and a renowned artist of Bengal. There is a myth that runs in the family that they had once received a massive treasure , but all traces and trails of it had been lost. Sona da along with Abir and Jhinuk join a festivity in that mansion in Durgeshgor and stumble upon the lost clues that may lead them in unearthing one of the greatest treasures of Bengal.