A robbery gang terrorized the Tamil Nadu. The police officer Mahesh is charged to dismantle the gang. Mahesh lives with his widow, blind sister Vidya, and his niece Anu. The reporter Vimala compels Mahesh for an interview, but he refuses. She later finds herself swooning over his investigative intellect. They later fall in love with each other. Guruji, the local gang-buster, then becomes discomposed with Mahesh for falling in love with Vimala, his ex-fiance. In the past, Mahesh was a happy-go-lucky and immature youth. Furthermore, Mahesh hated the police while his brother-in-law, a police officer, was in charge to catch the robbery gang. His brother-in-law was later killed in a bomb blast, and his sister became blind. To take revenge, Mahesh became a police officer. The rest of the story is about how Mahesh catches the robbery gang and its leader Guruji.

Thenkinnam is a 1971 Indian Tamil film released on 1971. The film is directed by K. Krishnamurty, produced by K. Krishnamurty.