Based on the story Ranir Ghater Brittanto by Syed Mustafa Siraj, Faltu is the story of a boy leading an aimless life until he suddenly finds purpose in the innocuous query of a census official - “Who is your father?”

Faltu's mentally ill mother had died in childbirth. The little that he knows of her is that she came as a waif to the little hamlet of Ranigarh where he grew up. The official's question leads him to go in search of his father and his identity, opening up a veritable Pandora's Box. His discovery that he is the son of a man who raped his mother throws his life into turmoil.