Theethum Nandrum begins with a robbery at a petrol bunk by three burglars Siva, Daas and Maaran are repeated offenders, but manage to escape scot-free. Daas and Siva are close friends, and their equation remains the same even after the former gets hitched to Sumathi. Though Sumathi requests Daas to bid adieu to compulsive crime, he commits the illegal act again, along with Siva and Maaran.
