After the death of his wife, Gurupada Mitter (Prasad Mukherjee), an advocate, has not been at peace. He and his daughter Buchki (Gitali Roy), meet Birinchi (Charuprakash Ghosh). Birinchi Baba claims to be ageless. He tells stories from the past; about his arguments with 'Plato' about time, how he taught E=mc2 to Einstein, and was on first-name terms with Jesu (Christ) and Gautam (Buddha). Birinchi Baba has a growing band of rich devotees.
Gurupada decides to patronize the holy man and become his disciple. Daughter Buchki is disappointed with her lover Satya. To teach him a lesson, she tells Satya that she is going to leave him and become a disciple of Birinchi Baba.
Satya turns to his friend Nibaran for his help. It does not take Nibaran long to realize that Birinchi Baba is a fraud. Nibaran and friends expose Birinchi Baba. The devotees feel foolish and perhaps have learnt a lesson.
Charuprakash Ghosh as Birinchi Baba
Rabi Ghosh as Birinchi Baba's assistant
Somen Bose as Nibaran da
Satya Bandopadhyay as Nitai da
Haridhan Mukherjee as Ganesh Mama
Satindra Bhattacharya as Satya
Santosh Dutta as Professor Nani
Geetali Roy as Buchki
Prasad Mukherjee as Gurupada Mittir
Renuka Roy as Nani's wife
The Academy Film Archive preserved Mahapurush in 2005.