Set during British rule, Thangalaan follows a fierce tribal leader, Thangalaan, and his tribe who assist Lord Clement, a British General, in locating hidden gold in their village. As they search for the treasure, they incur the wrath of Aarathi, a mysterious sorceress. Thangalaan embarks on a relentless mission to confront and stop her, using all his strength and courage to protect his people and their land.