Plot
Vinayak Rao narrates the tale of the goddess of prosperity, the symbol of endless gold and grain, and the mother of all the gods. Her greedy offspring Hastar acquired all her gold, but the other gods banded together and destroyed him when he went for the grain. The Goddess saved his life by sheltering him inside her womb, on the condition that he would be forgotten. However, the residents of Tumbbad built a temple for Hastar's worship, provoking the gods who cursed the village with incessant rain.
In 1918, Vinayak's mother, a widow, is the mistress of the zamindar Sarkar and hopes to get a share of his mysterious treasure. Vinayak and his brother, Sadashiv, bastard children of the zamindar, stay home with a disfigured and starving old woman, supposedly their paternal grandmother, chained in a separate room. One day, while their mother is away, Sadashiv gets injured after falling from a tree, and their mother takes him away to get help. Vinayak tries to feed the woman in exchange for information on the treasure, but she escapes and tries to eat him instead. He invokes the name of Hastar, making her fall into a slumber. Sarkar and Sadashiv both die, and Vinayak and his mother leave for Pune.
Fifteen years later, Vinayak returns to his home in Tumbbad, looking for Sarkar's treasure. The old woman still lives, with a tree growing out of her body, and offers to reveal the treasure's location if he ends her suffering. She leads him to the goddess’ womb, located inside Sarkar's mansion, and teaches him to retrieve the treasure. Inside the womb, Hastar dwells, hungry for eons as he was denied the Goddess’ grain. Vinayak descends into the womb with a rope and draws a circle of flour to protect himself. He then lures Hastar with a flour dough doll, and when he is distracted, steals gold coins from Hastar's loincloth and quickly flees the womb.
Vinayak burns the woman, and keeps traveling from Pune to Tumbbad to retrieve more coins, selling them to his friend and moneylender Raghav, who wonders about the source of Vinayak's newfound wealth. He follows Vinayak to Tumbbad, who tricks him into entering the goddess' womb. Raghav picks up a dough doll kept as a bait inside a container, causing Hastar to attack Raghav, fusing him to the walls of the womb. Upon seeing Raghav's mutilated and grotesque condition, Vinayak burns him to end his suffering.
In 1947, Vinayak is consumed by greed and decadence, and faces a deteriorating family life. He trains his son Pandurang to retrieve Hastar's coins and takes him to Tumbbad, warning him not to bring a dough doll for the practice. Pandurang brings it anyway, and Hastar attacks them, but they both narrowly manage to escape. Vinayak later learns that Sarkar's mansion was appropriated by the newly formed government of independent India. He goes back to Tumbbad, hoping to secure as much gold as possible before he loses the mansion. Pandurang suggests stealing Hastar's entire loincloth, and tries luring him with multiple dough dolls. However, Hastar multiplies into many clones inside the womb, trapping them. As a last resort, Vinayak ties the dolls around himself and faces the attack of Hastar and his clones, allowing Pandurang to escape. Once outside the womb, Pandurang encounters Vinayak, now cursed like the old woman, who offers him Hastar's loincloth. Pandurang refuses, and after putting him to sleep by invoking Hastar's name, burns him and leaves Tumbbad.
