Pandiyan aka “Pondy Pandi” (Vijay Sethupathi) is the son of a Puducherry-based police inspector P. Meena Kumari (Raadhika). Despite being an inspector’s son, he grew up being friendly with the criminals behind bars and on reaching adulthood, unknown to his mother, he becomes a rowdy, though an incompetent one.
Pandi comes across a deaf girl Kadhambari (Nayantara) and immediately falls in love with her. Kadhambari is the daughter of a sincere police officer Ravikumar (Azhagam Perumal), who is in pursuit of Killivallavan aka Killi (Parthiban), a dreaded gangster and politician who had killed Ravikumar’s wife and had caused Kadhambari to lose her hearing in her childhood. Kadhambari seeks Pandi’s help in finding her father, who has not spoken to her for the past two days, to which he agrees. Pandi soon learns that Ravikumar had been killed by Killi, but hides the matter from Kadhambari as it would make her upset. But Kadhambari learns about her father’s death from Meena Kumari and is determined to avenge his death by going after Killi and killing him. Pandi agrees to help her in her mission, with the promise that he will hold Killi’s shoulders while she stabs him.
Pandi and his gang along with Kadhambari hatch a plan to kill Killi while he is travelling. However, this is foiled as their plan gets mixed up with that of Mansoor (Mansoor Ali Khan), the political rival of Killi who wants to contest the upcoming election in place of Killi’s wife Baby (Meenakshi). Pandi’s gang is enraged and despite Paandi’s reassurances, decide not to help Kadhambari further. Kadhambari decides to go ahead on her mission on her own as she does not want Pandi and his friends to split up over her. She reaches Killi’s hideout, but on attempting to kill him, he knocks her out. Pandi soon arrives at the hideout and he and Kadhambari, who has regained consciousness, try to kill Killi, but it fails as Kadhambari is unable to stab him. At this juncture, Mansoor arrives at the hideout; both he and Killi stab each other to death, with Pandi falsely taking credit for their deaths in order to impress Kadhambari. Ultimately, Pandi, disillusioned with the rowdy lifestyle, becomes a police officer as per his mother’s wishes, despite Kadhambari’s reservations.