In 1850, in the village of Veppur,
North Arcot, Thangalaan resides with his wife, Gengamma, and their children. As the village chief and a landowner, he is highly respected, unlike most of his fellow villagers who are bonded labourers on the
zamindar's land. Thangalaan often regales his children with bedtime stories, and one night, he narrates a chilling tale about Aarathi, a woman from the Nagar tribe, believed to be a sorceress and protector of the land in the deep forests. Thangalaan's great-grandfather, Kaadaiyan, belonged to a tribe skilled in extracting gold from the Ponnar river sand. When a king, passing through the area, discovered the mountain's
gold veins, he sought Kaadaiyan's expertise to retrieve the gold. However, Aarathi had set up obstacles, including snakes, to safeguard the territory. Kaadaiyan initially refused to help the king but was promised the land his forefathers had lost to the king's ancestors, which had been
gifted to the Brahmanas. Kaadaiyan eventually agreed, but the king found the retrieved gold rocks fake, attributing it to Aarathi's sorcery. The enraged king beheaded a
Buddha statue after being urged by a Brahmin priest, who cited Buddha as a sorcerer. A fierce battle ensued between Aarathi and Kaadaiyan's men, resulting in Kaadaiyan slitting Aarathi's abdomen, unleashing a torrent of blood that flowed over the land, transforming the sand into gold. Gengamma interrupts Thangalaan's storytelling as their children have already fallen asleep. In an attempt to seize Thangalaan's land, the zamindar's men set fire to the farm produce, rendering Thangalaan unable to pay the taxes. Consequently, his land is transferred to the zamindar, and Thangalaan and his family are forced into
debt bondage. Meanwhile,
British officer Lord Clement arrives in Veppur, seeking gold, and is aware of the villagers' ancestral expertise in tracing it. The villagers fear Aarathi, but Thangalaan, his son, Asokan, fellow villagers Varadhan, Gengupattar, and others embark on a journey northwest. Thangalaan begins
hallucinating Aarathi's presence, warning him away from the forest, but he presses on, overcoming challenges like a river, a black panther, a sandstorm, and snakes. Upon reaching a trench created by a lightning strike, Asokan discovers the beheaded Buddha statue, and Aarathi frightens him from underwater. Undeterred, they find the remaining remnants of the statue with gold traces at the bottom. However, during the gold extraction, lightning strikes Clement's son. Clement vows to find the gold ore at any cost, thanking Thangalaan for leading them to the site and gifting him his son's clothes. Clement also provides daily wages, while Thangalaan returns to the village, boasting of better pay and respect. He gifts the village women
blouses, tempting them to join the
gold mining effort. The entire village, including the women, set off to the barren forest, only to meet their fellow villagers lamenting for being exploited by British and Indian middlemen, who had deprived them of necessities, as they had only found a few iron and silver ores. Thangalaan remains resolute in his gold pursuit at the same site despite Asokan getting
possessed with Aarathi and warning the group to abandon the mining work and return to their village. Thangalaan, however, recalls his dream and finds a small rock matching the one in his dream, insisting on digging the
lode deposits nearby. But,
snakes attack him, one of which fatally bites his younger daughter. Aarathi's intervention prevents Thangalaan from saving her. Despite the lack of food, wages, and amenities, Clement, with Thangalaan's help, continues the work, and they discover a deep, abandoned mine. As they enter it, Thangalaan recognizes a place similar to his dream and finds streaks of gold. In the chaos that follows, the British claim the gold as their own, leading to a fight in which Arasani is shot. However, the gold stones were just clay, courtesy of Aarathi's sorcery. Their settlements are destroyed in a fire, but they are given hope to continue mining. The starving population spots a
buffalo, which Thangalaan reminisces of Aarathi and kills the buffalo, after which they all consume. Later, he motivates the group to dig deeper, where Aarathi, in her present birth, appears with her men, attacking them ruthlessly. Aarathi subdues Thangalaan, using her sorcery to reveal his past lives. Thangalaan recalls being Arasan "Aaran", a tribal king, and his wife, Aarathi, in the 5th century, protecting the land's resources, mainly gold. Aarathi safeguarded the land while Aaran set off to fight trespassers but was defeated and, in his subsequent births as Adhi Muni, Kaadaiyan, and Naga Muni, he became a slave to dominant communities, facing
discrimination and
ostracism. Their oppressors forced him and his men to labour and extract gold. Thangalaan pleads with Aarathi, acknowledging their duty to protect the land and prioritising the community's welfare, which was neglected. The dying Aarathi grants permission for Thangalaan to fetch the gold, but only for his community's benefit. Enraged by Clement's attack on Aarathi, which fatally slit her abdomen, Thangalaan kills him and the other officers, declaring that the land and its resources are hereby their own, not to be exploited by foreigners. With newfound determination, Thangalaan single-handedly ventures deep into the mine and finally discovers an
abundance of native gold, bringing joy to his community. At the end of the film, when another group of British and Indian troops arrived, Thangalaan and the villagers were defending the place. ==Cast==