Two human skeletons are discovered from the property of Supriyo Mukherjee, a wealthy industrialist and influential figure. The day Nalinikanta arrives with his wife to investigate, Supriyo Mukherjee is also murdered.
While investigating Supriyo Mukherjee's murder, Nalinikanta interrogates his former student and Supriyo's wife, Imon. Although not present on the murder day, she confesses to an affair with Supriyo and being pregnant from it.
Nalinikanta investigates various leads: the escape of two girls from Supriyo's home, worker unrest, ties with Judhistir Williams, and the death of Nandini's ex-lover. The autopsy report reveals Supriyo Mukherjee was poisoned, not stabbed.
Judhistir Williams threatens Nalinikanta but, refusing to be intimidated, sends people to attack him and his wife, Paroma. Nalinikanta responds with a counterattack.
Suspicion narrows to one person. Nalinikanta shifts from a physics to a math approach to justify this. Meanwhile, Mustak discovers the identity of the person who attempted to kill Supriya with a knife.
Nalinikanta figures out how the murder was committed through poisoning. When he goes to arrest the real culprit, the suspect flees and heads towards Judhistir. Nalinikanta chases him, leading to a dramatic gunfight.
