Subarna Sen, an Oxford University professor, travels to India after the death of his maternal uncle. He learns that his uncle's palace has a hidden treasure and decides to find it.

Prof. Subarna Sen along with Abir and Jhinuk, visits his student's ancestral mansion in Durgeshgor. Once there, the trio comes across a vital clue that could lead them to one of the greatest treasures in Bengal's history.

Sona Da, Abir and Jhinuk come across a riddle that turns their vacation into a dangerous quest for the hidden treasure of King Shashanka, one of the best-kept secrets of Bengal.