Kathiresan aka Kaththi, a criminal, escapes from the Kolkata prison and comes to Chennai, where he comes across his doppelganger Jeevanandham, fighting for his life after being shot at by unknown men. Kathir decides to pass off as Jeeva and make away with a lump sum amount but once he realizes who Jeeva really is, Kathir turns a crusader.

Kaththi

The brother of a local law minister, who is out on parole and should be back in custody in the next six days, goes missing. When he doesn't show up on the sixth day, the opposition party blames the law minister for keeping his brother in hiding, and therefore, resulting in his immediate arrest. Meanwhile, the missing brother resurfaces and wants to avenge his captor but he doesn't have a clue about his identity or whereabouts.