Tiruppachchi movie starts at Tirupachi, a village near Madurai where Sivagiri (Vijay) makes his living by making famous Tirupachi Aruvaal. His whole ambition being bringing up his most dear sister, Karpagam(Mallika). He wants to see her married to the best guy of his reach. He marries her to Sai, a nice guy who runs a college canteen in Chennai. After marriage they shifts to Chennai.
Sivagiri's associate Kannapan (Benjamin) gets a visa to Dubai and to see off him Sivagiri reaches Chennai. He gets to know that a Mafia controls Chennai and they mishandles his sister and husband. Sivagiri decides to risk his life, finish off the Mafia to give Karpagam a peaceful life.