The movie revolves around the unwanted incidents that happened in the princely state of Ratnagarh. After the murder of King Chandrakanta, one Dr. Palit (Kamal Mitra) asked for help from one Detective Smarajit Sen (Sisir Batabyal), as a family friend. Detective Sen sent his assistant Bimal to Ratnagarh to investigate and ascertain the security of young Kumar Bahadur, a new predecessor of the royal family of the estate. They observed that a mysterious lady Manjusri (Manju De) sang an uncanny song in the adjacent water body near the palace. Mr. Gupta (Bikash Roy), a suspicious botanist who stayed in the neighborhood also roamed in that locality. It revealed that he was deprived of the real property of the royal family and took revenge by killing the members of the family. He used one deaf and dumb porter as a hired killer. Ultimately, he was killed by the detective at the end before he could commit another murder.