Story and Plot:
Story plot is 1933. Nand Dulal Babu was renowned person of his time. His age is near 55 but because of a strange addiction of Spider Serum has made him looking 70 year of age.
A day while Ajit is walking with byomkesh, meets his very old friend Mohan, who is a doctor. Mohan tells them about Nand Dulal Babu and his addiction because of which he is getting Irascible, Fathead and Cruel day by day. The Serum is a type of drug which is dangerous for him, but doctor as well as Nand Dulal's family members are not able to find the source how he is getting this drug.
Byomkesh is busy, so he give this amenability to Ajit to solve the case. The episode reveals how Ajit tries to find out the source of "Makdi Ka Ras"
What is Addiction of Makdi Ka Ras?
In the start of the episode Mohan explains the duo about Tarantula Spider Serum (or extracts) which is a well known drug of America. The drug directly impacts to a person's nervous system and makes him cantankerous. It also hurts his health.