Based on true events, Taanashah narrates the life and journey of a dreaded dacoit, Shiv Kumar Patel who ruled the land of Bundelkhand for over twenty-eight years with his cunning brilliance and had the entire police, administration and politicians going by his word. Shiv Kumar took to arms due to his father's murder by a local upper-caste tyrant Daddan after which he avenged his father's death and went on to become the most powerful criminal in the area.