Daily wage laborer Rengasamy makes a living carrying cardamom sacks from the mountains to the foothills of the Western Ghats in the interior of Tamil Nadu. Chacko, a communist from Kerala, unionizes these workers to prevent the estate owner from exploiting them. As a result, there are frequent clashes between the landlord and the union members.

Rengasamy wants to buy a piece of land from a local, but fails due to objections from the seller's family. He marries his cousin Eshwari, who is a worker on the estate, and joins her union. His second attempt to buy land ends in unexpected tragedy and he loses most of his savings. He later acquires land with a loan and begins farming to pay back the debt.

Meanwhile, in the communist party office, Chacko has a heated debate with a senior comrade about industrialization and the workers' conditions. Another comrade sends Chacko to deliver a message, and while he is away the estate owner closes the estate to make the workers and union members suffer. When Chako returns, the estate owner mocks him, saying that he had plotted with the senior comrade for this purpose.

Angered, Chacko finds the workers who are preparing to leave. He gathers a few of them, including Rengasamy, to take up weapons and confront the estate owner. The mob finds the estate owner with the senior comrade, kill both of them, and are jailed for several years. When Rengasamy returns home, the fertilizer vendor forecloses on his land for outstanding debts. Rengasamy later becomes a security guard for a windmill constructed on the land he once owned.