After shining in many path-breaking films sch as Raam and Katradhu Tamizh, hero Jiiva is all set to attempt an image makeover. Thenavettu proves his special skills as mass action hero.

Kottaisamy (Jiiva) and his chum Vellaiyan (Kanja Karuppu) come to Chennai in search of a lucrative career. Illiterate and only suited for hard labour, Kottai and Vellaiyan join city dada Kailasam (Ravi Kalai)'s gang as apprentices in crime. Both are given the responsibility of maintaining and supplying weapons to the whole group engaged in settling disputes and problems across the city.

In due course of time, Kottai and Vellaiyan come to know about their employer's other ominous side. However, for the sake of money and a permanent career, they try and restrict their involvement to the job at hand. In the meantime, Kottai also falls in love with Gayathri (Poonam Bajwa) an orphan he meets in the city.

When everything moves at a smooth pace, Kailasam's son Santosh (Sabeer) who meddles with young, beautiful women, misbehaves with Gayathri. Angry and hurt, Kottai is forced to intervene and settle the issue. He brutally attacks Santosh and admits him in hospital. Kailasam sees his son's hammered state, is terribly shaken, and sends his men on a thorough search for the mysterious man's identity who had had the guts to beat up this powerful gangster's son.

After a point, thinking about the repercussions, Kottai confesses to his boss that it was he who attacked Santosh and that he did so to save his fianc閑. Later, Santosh dies. Terribly upset, Kailasam goes wild and goes behind Kottaisamy and Gayathri with a mounting vengeance to eliminate them. The lovebirds flee from the city and take refuge in the Koothandavar temple among the large crowd of eunuchs gathered there for their annual worship. The climax reveals Kottai and Gayathri's destiny and whether they escape from Kailasam's men.

Director V.V. Kathir has taken up an action theme in his debut. Cameraman Vetri has provided maximum aid to establish the intensity of the story. However some crazy and inexplicable angles of the camera during the action sequences do not convey the spirit of the scenes and are not enjoyable. 'Usilampatti' in Srikanth Deva's music is good.

Hero Jiiva has absolutely made up his mind to test his commercial viability as an action hero. He has also transformed himself in all possible ways to suit the role and has performed his best in the action entertainer. Though Seval released earlier than Thenavettu, this is technically heroine Poonam Bajwa's debut in Tamil. She has also done a good job. Kanja Karuppu's role is passive yet strong. Thenavettu is good in parts.