This socially relevant drama delves into the twists and turns in the life of Balan Mash (Mammootty), an art teacher who lives in a tiny hamlet in Kerala. He has a serene life, with two children, a wife, a mother and a revolutionary brother - Gopi(Mukesh), a typical kootu kudumbam, or joint family, of Kerala.
Balan Mash has an uncle who is mentally challenged. His uncle became a mental patient after a separation with his lover; this underlines the deep-rooted belief among their family that one male from each generation will go mad as a person from their past generation had sinned by throwing the idol of 'Devi' in a well.He was cursed by the goddess and became a lunatic. This curse would pass down through generations.
When Balan Mash's uncle finally dies, the talk of the town becomes, 'who would be next – Balan or Gopi?'
One night changes it all, when Balan has a nightmare. People start suspecting Balan of following the footsteps of his uncle into madness because Balan's uncle (Babu Namboodiri) fell mentally ill with a nightmare.
Now Balan's community evaluates each and every move he makes; he is deemed a lunatic and his actions are misinterpreted. Eventually his family joins the gang and he is sent to the asylum. The doctor declares him sane. But society doesn't agree. Helpless, Balan plays mad. How can Balan survive in a world that has already labelled him? Can he ever find a way out of all the 'madness'?