In a battle for prestige, a political greenhorn will take on rank outsider and fellow son of the soil in a triangular contest here that will gauge the voters' mood of the two year-old K Palaniswami government.
An endorsement or rejection of the ruling party nominee P Raveendranath Kumar could assume significance as he is contesting from his father and Deputy Chief Minister O Panneerselvam's home turf of Theni.
The next assembly elections in Tamil Nadu are scheduled in 2021.
Congress has fielded former union Minister E V K S Elangovan and rival AIADMK leader T T V Dhinakaran's AMMK is banking on his earlier stint as then Periyakulam MP to spring a surprise against the other two.
Thanga Tamil Selvan had earlier represented Andipatti, an Assembly segment falling under Theni.
Agriculture being the main vocation in the district, drinking water supply, civic amenities, including proper drainage facilities, jobs and raising the height of the Mullaperiar Dam, an inter-state issue involving Kerala, are key demands of the locals.
The contest being a triangular one, the three main contestants are leaving no stone unturned to secure a victory, and embark on a hectic campaign schedule from dawn till the presecribed hours through the day.
Though new to electoral politics, Raveendranath Kumar exudes confidence of winning with much ease in what he termed as "AIADMK's fortress."
Countering criticism of dynasty politics when he was nominated from the southern segment, Kumar brushes aside the charges, saying he has been in active politics for many years, having "grown from the grassroots level" and being appointed to various party posts earlier.
"There is massive public support for us. No party can defeat us as this is AIADMK's fortress," he said about Theni.
Though the ruling party won the seat in 2014, Congress emerged victorious in in 2009 and 2004. AIADMK's R Parthipan snatched it from the national party in 2014, following a 74 per cent turnout.
Kumar's promises include job creation and striving to increase the height of the Mullaperiyar Dam to 152 feet.
The inter-state row revolves around the dam located in Kerala's Idukky district and maintained by Tamil Nadu, over its structural strength.
Following a legal battle between the two states, the Supreme Court in 2014 held that the over 120 year-old dam was safe and allowed Tamil Nadu to raise water level to 142 feet and ultimately to 152 feet after completion of strengthening measures on the reservoir.
It caters to five southern districts of the state, including Theni.
Kumar believes he will also romp home riding on the track record of the AIADMK government in implementing 'visionary schemes' of 'Amma', the late J Jayalalithaa, and the "powerful" Two Leaves symbol.
However, Thanga Tamil Selvan does not take Kumar seriously.
"This is a direct contest between me and EVKS (Elangovan). Only the media is highlighting Kumar being the son of Panneerselvam, but there is no such euphoria among the people," he said.
Banking on Dhinakaran's previous stint as then Periyakulam MP, the disqualified MLA believes his leader's hard work will pay off, as the AMMK leader "has been to all villages, met a lot of people, and enjoys a good reputation."
He is confident of a "grand victory" and his promises to the electors include provision of safe drinking water, the Mullaperiyar issue and implementing the Dindugul-Sabarimala railway line.
He also vows to lend his voice against the India-Based Nutrino Observatory if elected as Member of Parliament, saying AMMK had earlier staged a protest against it since the locals are up in arms against the scientific venture at Pottipuram in Theni.
Congress' Elangovan,known for his outspoken but sometimes controversial statements, is battling the "outsider" tag as he is a native of Erode in western Tamil Nadu.
However, he shrugs it off, saying he "belongs to all of Tamil Nadu."
Grandson of rational leader, the late E V Ramasamy Periyar, the former TNCC chief recalls politics running in the family and says they have been serving the people for long.
"Whether it is me or my family, including my grandfather (Ramasamy), we have been striving for social justice for the last many years.
I belong to whole of Tamil Nadu. Theni is not a foreign constituency to me," he said.
A nominee of the DMK-led Secular Progressive Alliance (SPA), Elangovan says he is contesting "with a faith on the people" and vows to defeat the AIADMK alliance, whose constituents include BJP.
In his campaign, he trains his guns against the BJP and its policies, while claiming the voters are also against the ruling AIADMK in Tamil Nadu.
His assurances include making Theni a "big tourist spot" as it lies in the foot of the picturesque Western Ghats.
The constituency is dotted with six Assembly segments, including two Reserved ones.
While AIADMK bagged all of them under Jayalalithaa in 2016, bypolls to Andipatti and Periyakulam are being held simultaneously on April 18.
There are about 10.75 lakh voters in the Theni Lok Sabha segment.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)