The sudden demise of his maternal uncle leaves budding lawyer Abir in charge of his ancestral property. Accompanied by his friend, philosopher, and guide Subarna Sen, aka. Sona da, Abir visits his ancestral mansion only to figure that his uncle has left behind for him a series of clues to unearth the hidden treasure of Mughal prince Shah Suza kept secured within the property. Jhinuk, Abir's crush, joins them in the quest. Soon, Sona da, Abir, and Jhinuk are caught in a web of mystery and deceit.

Sona da with Aabir 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 rumour 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 is revealed testing Sona da`s wit and grit one more time leading towards the discovery of one of greatest treasures Bengal has ever witnessed.

The third film in the Sona Da Franchise. Watch how a blissful vacation turns into a quest of one of the greatest treasures that Bengal has ever known.