Searching for work in the city, Ranganathan meets a thief named Raju. They advise each other to change their lives, inadvertently swapping paths: Raju becomes an honest man, while Ranga turns into a ruthless hitman.
Years later, Ranga's long-lost sister, Laksmi, is married and has a son, Suresh. After Raju saves Suresh from a thug, a grateful Laksmi hires him as her son's guardian. Unaware of their identities, Ranga takes a contract from his associate Ganga to collect money for gang leader Ravi, who subsequently hires Ranga to kidnap Suresh for ransom.
Ranga infiltrates Laksmi's home disguised as an additional guardian. When Ranga realizes Raju is protecting the boy, he challenges him, determined to finish the kidnapping. However, Ravi double-crosses Ranga, revealing Laksmi is his sister. Captured by Ravi's thugs, Ranga is rescued by Raju. Ravi is imprisoned, and Ranga joyfully reunites with his sister, living happily with Raju and Ganga.