Muniyan, a cycle-rickshaw puller, is a road-side dweller along with his wife Valliamma and their seven children – two daughters and five sons. Despite being the sole breadwinner of his family, Manian spends the majority of his meager earnings on liquor. His wife struggles to make ends meet with the remaining amount. Her friend Rakkamma, a street food vendor, lends financial support to Valliamma's family.

The educated Krishna, one of Manian's sons, elopes with a girl and separates himself from the family. Manian's daughter Kuppamma along with her friend Chellamma contribute a small income to the family by picking up rags on the roads. Rangan, a kindhearted lorry driver, befriends Kuppamma and offers assistance to her whenever she is in need of any help. They both get close to each other and their friendship leads to a physical relationship. When Valliamma gets to know this, she commits suicide fearing that Kuppamma's act has brought disgrace to the family. Meanwhile, Kuppamma gets shocked when she learns that Rangan is already married. With an intention to not disclose Rangan's identity, she keeps herself away from him. During this time, Kuppamma finds out that she's pregnant. Despite the advice of fellow road-side dwellers to abort the child, she refuses to do so. She also protects Rangan's identity by informing her relatives that her lover had died in an accident.

Knowing that she is about to deliver their child, Kuppamma wishes to meet Rangan. But Rangan had relocated to another locality after she turned down his support. When Rangan's wife gets to know of the relationship, she empathises with Kuppamma and insists that Rangan bring her to their home. When Rangan reaches the slum, he finds Kuppamma in throes of labour pain. Kuppamma dies soon after, upon delivering their child. Rangan and his wife then decide to adopt the child as penance for Rangan's sins.