Nishanath Sen starts receiving anonymous threats at Rosy Mansion, where everyone lives precariously under the shadow of their dark past. Nishanath knocks on Byomkesh Bakshi's door for help in deciphering the cryptic threats.
Nishanath Sen abruptly stops the investigation after Byomkesh and Ajit's visit to Rosy Mansion. However, destiny brings Byomkesh back to the colony after he gets a sudden call from Bijoy.
The sudden demise of Nishanath Sen makes everyone in the colony a suspect. As Byomkesh starts the investigation by searching for missing Rashik and an old convict Laal Singh, more deaths follow.
